This script creates a shop script to be used with the custom currencies script.

CustomShop.rb

#==============================================================================
#  Guild Curency Shop
#  ----------------------------------------------------------------------------
#  Version: 1.0
#  Author: Kalacious (AKA: VindictivePersonality)
#  License: GPL 3.0
#
#  Compatibillity Issues
#  ----------------------------------------------------------------------------
#   
#  There should be NO compatibillity issues what so ever. How ever if there are,
#  Please let me know.
#
#  REQUIREMENTS!
#  ----------------------------------------------------------------------------
#
#  Requires the currency generator script.
#
#  Any things that requires the currency to be passed in, MUST exist
#  in the currency hash thatis created in the currency generator script.
#
#  TOS
#  ----------------------------------------------------------------------------
#  If you know the GPL version 3, you know the answer, but this still applies:
#
#    Script for RGSS 3 ONLY adds abillity to generate shops.
#    Copyright (C) 2013 Kalacious (AKA VindictivePersonality)
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>
#
#
#==============================================================================
#  How to Use?
#  -----------
#
#  This script is suppose to be used with currency script, infact you need it 
#  in order to use this script :D.
#
#  This script also is designed to create either one shop based on one currency
#  or you can use the script methods to create multiple shops based on one
#  currencie.
#
#  We are going to dwelve into how to use the hash array to create a shop and 
#  how to create a shop for multiple currencies based on the script calls we
#  have out ligned below.
#
#  SHOPS::SHOPS_HASH
#  -----------------
#
#  This hash is used to create a shop object based on the the currency and
#  the items passed in. Please note that ALL the arrays in the hash MUST
#  be the same length or we may cause errors and issues.
#
#  This hash must be created as such:
#
#  SHOPS_HASH = {
#      'Currency' => {
#          :item_type => [0, 0, 0] #0 item, 1 weapon, 2 armor.
#          :item_id   => [0, 1, 2] #item_id's.
#          :price     => [10, 10, 10] #price for each item.
#       } 
#  }
#
#  This hash example, will create one shop with three items using the 
#  key as he currency to which the shop uses when buying or selling objects.
#
#  Please note, the key in this hash, the main key, needs to exist in the 
#  currency hash in the currency script. If not then this script will fail.
#  YOU CANNOT USE GOLD! This script only works with custom currencies. 
#
#  So now that we have a hash object, go ahead and call the shop. Wait how 
#  do we do that? Don't worry we will get to that. Lets relax for now and move
#  on to creating a master inventory list via script calls
#
#  $kc_shop
#  --------
#
#  This object will allow you to create a master inventroy list based on the
#  the items you pass it. Much like the hash object above you will use
#  these script calls to create a master inventory list and then pass it to a
#  shop object.
#
#  $kc_shop.create_item(item_type, item_id, price)
#
#     --> This will create ONE object in the @inventory, which
#         is called the the master inventory list.
#         This is what you use to create your item for the shop.
#
#  $kc_shop.inventory
#
#     --> This will return you that master inventory list with
#         all the items in it.
#
#
#  $kc_shop.create
#
#     --> DONT call me. there is no need for that. You would only
#         create the array from the hash below twice.
#
#  So how do I use this to create a shop?
#
#  You would call the first two script calls like such:
#
#
#     $kc_shop.create_item(0, 1, 10)
#     $kc_shop.create_item(0, 2, 10)
#     $kc_shop.create_item(0, 3, 10)
#     puts $kc_shop.inventory #[[0, 1, 10][0, 2, 10][0, 3, 10]]
#
#  Ok so we either created a hash object for the shop or we created the 
#  master inventory via the script calls. HOW DO WE CALL THE SHOP?!
#
#  Module GS
#  ---------
#
#  This module is used for one of two things, calling a shop or ....
#  calling a shop. The difference between the way you call the shop
#  is what you pass in and which method you call.
#
#  call_shop(master_inventory, 'curr', puchase_only = false)
#       
#       ---> The master_inventory is $kc_shop.inventory pased in.
#            curr is the currency you want the shop to repersent.
#            purchase_only is set as false by default.
#
#       ---> Use this ONLY if you are using $kc_shop as a script
#            call to create items.
#
#  create_shop('curr', purchase_only = false)
#
#       ---> This is called ONLY if you are using the hash, you pass in the
#            currency from the hash, the main key, this then uses that to
#            create a shop based on that currency in the hash below.
#
#==============================================================================
# ** SHOPS
#------------------------------------------------------------------------------
#  This module is used to set up a shop for a particular currency. This will
#  only create ONE shop per currency. You cannot create multiple shops per
#  currency.
#==============================================================================
module SHOPS
  #--------------------------------------------------------------------------
  # * Create your shop objects here based on a particular vocab.
  #--------------------------------------------------------------------------  
  SHOPS_HASH = {
    'GC' => {
      :item_type => [0, 0],
      :item_id => [4, 5, 6],
      :price => [10, 14],
    },
    'RT' => {
      :item_type => [0, 0],
      :item_id => [1, 2],
      :price => [10, 14],
    }    
  }
end
#==============================================================================
# ** GS (GuildShop)
#------------------------------------------------------------------------------
#  This module is used to create a shop and pass in an inventory or used 
#  to create a currency based shop based on the hash above.
#==============================================================================
module GS  
  #--------------------------------------------------------------------------
  # * Call a shop based on the master_invenotry list, type of
  #   currency the shop uses and eather it's purchase only or not.
  #--------------------------------------------------------------------------   
  def self.call_shop(master_inventory, curr, purchase_only = false)
    SceneManager.call(Scene_Guild_Shop)
    SceneManager.scene.prepare(master_inventory, curr, purchase_only)
  end
  #--------------------------------------------------------------------------
  # * Create a shop based on the currency, from the hash above and
  #   weather the shop is purchase only or not.
  #--------------------------------------------------------------------------   
  def self.create_shop(curr, purchase_only = false)
    $kc_shop.create(curr)
    SceneManager.call(Scene_Guild_Shop)
    SceneManager.scene.prepare($kc_shop.inventory, curr, purchase_only)
  end
end
#==============================================================================
# ** DataManager
#------------------------------------------------------------------------------
#  This module manages the database and game objects. Almost all of the 
# global variables used by the game are initialized by this module.
#==============================================================================
class << DataManager
  alias kalacious_guild_shops_game_objects create_game_objects
  def create_game_objects
    kalacious_guild_shops_game_objects
    $kc_shop = GS_Setup.new
  end
end
#==============================================================================
# ** Game_Guild_ShopObject
#------------------------------------------------------------------------------
#  This creates a new shop object that only accepts the item_type,
#  item_id and price of the said item.
#==============================================================================
class Game_Guild_ShopObject
  
  attr_reader :item_type
  attr_reader :item_id
  attr_reader :price
  #--------------------------------------------------------------------------
  # * Create a shop based on the currency, from the hash above and
  #   weather the shop is purchase only or not.
  #--------------------------------------------------------------------------   
  def initialize(item_type, item_id, price)
    @item_type = item_type
    @item_id = item_id
    @price = price
  end
  #--------------------------------------------------------------------------
  # * Returns @data_type[@item_type] based on the type.
  #--------------------------------------------------------------------------   
  def data_item
    if @item_type == 0
      return @data_items[@item_id]
    end    
    if @item_type == 1
      return @data_weapons[@item_id]
    end
    
    if @item_type == 2
      return @data_armors[@item_id]
    end
  end
  #--------------------------------------------------------------------------
  # * Get the price of the item.
  #--------------------------------------------------------------------------  
  def get_price
    return @price
  end  
end
#==============================================================================
# ** GS_Setup
#------------------------------------------------------------------------------
#  Used to create a master inventory based on either the item_type
#  item_id and the price or the currency vocab and the hash above.
#==============================================================================
class GS_Setup
  
  #--------------------------------------------------------------------------
  # * Create an empty inventory object.
  #--------------------------------------------------------------------------   
  def initialize
    @inventory = []
  end
  #--------------------------------------------------------------------------
  # * Return the inventory object.
  #--------------------------------------------------------------------------   
  def inventory
    @inventory
  end
  #--------------------------------------------------------------------------
  # * Create an inventory object based on the vocab and the hash above.
  #--------------------------------------------------------------------------   
  def create(curr_vocab)
    SHOPS::SHOPS_HASH.each do |key, value|
      if key == curr_vocab and $kc_currency.exists?(curr_vocab)
        value[:item_type].size.times { |i|
          item = create_item_object(value[:item_type][i], value[:item_id][i],
            value[:price][i])
          @inventory.push(item)  
        }
      end
    end
  end
  #--------------------------------------------------------------------------
  # * Create the Item assuming it doesn't already exist.
  #--------------------------------------------------------------------------   
  def create_item(item_type, item_id, price)
    if @inventory.any?
      @inventory.each do |inventory|
        if inventory[0] == item_type and inventory[1] == item_id and inventory[2] == price
          return false
        end
      end
    end
    item = create_item_object(item_type, item_id, price)
    @inventory.push(item)
  end
  #--------------------------------------------------------------------------
  # * PRIVATE - Creates the item array in the form of: 
  #   [item_type, item_id, price]
  #--------------------------------------------------------------------------   
  private
  def create_item_object(item_type, item_id, price)
    item = Game_Guild_ShopObject.new(item_type, item_id, price) 
    goods = [item.item_type, item.item_id, item.price]
    return goods
  end  
end
#==============================================================================
# ** Window_Guild_ShopBuy
#------------------------------------------------------------------------------
#  Creates a item list based on the item object passed in.
#==============================================================================
class Window_Guild_ShopBuy < Window_ShopBuy
  #--------------------------------------------------------------------------
  # * Makes the item list based on the object passed in.
  #--------------------------------------------------------------------------   
  def make_item_list
    @data = []
    @price = {}
    @shop_goods.each do |goods|
      case goods[0]
      when 0;  item = $data_items[goods[1]]
      when 1;  item = $data_weapons[goods[1]]
      when 2;  item = $data_armors[goods[1]]
      end
      if item
        @data.push(item)
        @price[item] = goods[2]
      end
    end
  end  
end
#==============================================================================
# ** Window Guild Currency
#------------------------------------------------------------------------------
#  Exactly the same as Window_Gold, the only difference is instead of getting
#  and displaying only gold, we get and display any currency passed in.
#
#  REQUIRES: Currency Script to work.
#==============================================================================
class Window_Guild_Currency < Window_Base
  #--------------------------------------------------------------------------
  # * Create a window, and set the @currency to the currency passed in.
  #-------------------------------------------------------------------------- 
  def initialize(curr)
    super(0, 0, window_width, fitting_height(1))
    @currency = curr
    refresh
  end
  #--------------------------------------------------------------------------
  # * Return a width of 160.
  #--------------------------------------------------------------------------   
  def window_width
    return 160
  end
  #--------------------------------------------------------------------------
  # * Clear the contents, draw the currency value.
  #-------------------------------------------------------------------------- 
  def refresh
    contents.clear
    draw_currency_value(value, currency_unit, 4, 0, contents.width - 8)
  end  
  #--------------------------------------------------------------------------
  # * Whats the currency unit?
  #-------------------------------------------------------------------------- 
  def currency_unit
    @currency.curr_sym
  end
  #--------------------------------------------------------------------------
  # * Get this currencies value.
  #-------------------------------------------------------------------------- 
  def value
    @currency.value
  end
  #--------------------------------------------------------------------------
  # * Upon open, refresh.
  #--------------------------------------------------------------------------   
  def open
    refresh
    super
  end 
end
#==============================================================================
# ** Scene_Guild_Shop
#------------------------------------------------------------------------------
#  Extends the Scene_Shop and creates, essentially, our own scene shop.
#==============================================================================
class Scene_Guild_Shop < Scene_Shop 
  #--------------------------------------------------------------------------
  # * Prepare the inventory, currency and weather its purchase only or not.
  #-------------------------------------------------------------------------- 
  def prepare(master_inventory, curr, purchase_only = false)
    @currency = $kc_currency.currency(curr)
    @goods = master_inventory
    @purchase_only = purchase_only
  end
  #--------------------------------------------------------------------------
  # * Create the currency window. (we use create_gold_window).
  #-------------------------------------------------------------------------- 
  def create_gold_window
    @gold_window = Window_Guild_Currency.new(@currency)
    @gold_window.viewport = @viewport
    @gold_window.x = Graphics.width - @gold_window.width
    @gold_window.y = @help_window.height
  end  
  #--------------------------------------------------------------------------
  # * Create the buy window.
  #-------------------------------------------------------------------------- 
  def create_buy_window
    wy = @dummy_window.y
    wh = @dummy_window.height
    @buy_window = Window_Guild_ShopBuy.new(0, wy, wh, @goods)
    @buy_window.viewport = @viewport
    @buy_window.help_window = @help_window
    @buy_window.status_window = @status_window
    @buy_window.hide
    @buy_window.set_handler(:ok,     method(:on_buy_ok))
    @buy_window.set_handler(:cancel, method(:on_buy_cancel))
  end 
  #--------------------------------------------------------------------------
  # * What happens upn buy?
  #-------------------------------------------------------------------------- 
  def do_buy(number)
    $kc_currency.decrease(@currency.curr_sym, number * buying_price)
    $game_party.gain_item(@item, number)
  end
  #--------------------------------------------------------------------------
  # * What happens upon sell?
  #-------------------------------------------------------------------------- 
  def do_sell(number)
    $kc_currency.increase_currency(@currency.curr_sym, number * selling_price)
    $game_party.lose_item(@item, number)
  end  
end