gistfile1.rb

<%
cost = product.product_costs.first
hide_qty ||= ''
unless cost.nil?
%>
  <%= form_for :cart, :url => {:controller => "cart"}, :html => {:multipart => true, :class => "form", :id => "product_form"} do |form| %>

    <% unless !hide_qty.blank? %>
      <label><%= t :quantity %></label>
      <select name="quantity">
        <% min = cost.min_quantity.blank? ? 1 : cost.min_quantity %>
        <% max = cost.max_quantity.blank? ? 20 : cost.max_quantity %>
        <% (min..max).each do |i| %>
          <option value="<%= i %>"><%= i %></option>
        <% end %>
      </select>
    <% end %>

    <%= hidden_field_tag 'product_id', product.id %>
    <%= hidden_field_tag 'product_cost_id', cost.id %>
    <%= submit_tag t(:add_to_cart), :class => "add-to-cart" %>
  <% end %>
<% end %>