original.rb

#!/usr/bin/env ruby

puts "How much IP do you have?"
ip_have = STDIN.gets.chomp #don't really need the STDIN
puts "Which champion do you want to buy?"
champion_want = STDIN.gets.chomp
lucian = #{lucian_value} #The #{} construct is for inside double-quoted strings, otherwise # just indicates a comment.
lucian_value = 6300
puts "#{champion_want} is #{champion_want} IP, so this means you need #{lucian_value} - #{ip_have}" #The math has to happen inside the #{} block... also, ip_have is read as a String, need to convert to an integer.


#If the user enters "lucian" I want it to be 6300.  so I can subtract the 6300 from the amount the user has (ip_have)
#need to test for an entry of "lucian", but that's step 2. For what you've got here, see the next file.

step1.rb

#!/usr/bin/env ruby

puts "How much IP do you have?"

ip_have = gets.chomp.to_i #to_i converts to an Integer.
puts "Which champion?"
champion_want = gets.chomp
lucian_value = 6300
lucian = lucian_value

puts "#{champion_want} is #{champion_want} IP, so this means you need #{lucian_value - ip_have}" #do the math in the block.

step2.rb

#!/usr/bin/env ruby

def champion_value(name)
  case name
  when "lucian"
    6300
  when "mudkipz"
    5
  when "baby lettuce"
    1002
  else
    return nil
  end
end
 
puts "How much IP do you have?"
ip_have = gets.chomp.to_i
puts "Which champion?"
champion_want = gets.chomp
value = champion_value(champion_want) #look up the value
if value #make sure we found the champion
  if value > ip_have
    puts "#{champion_want} is #{value} IP, so this means you need #{value - ip_have}" #do the math in the block.
  elsif value <= ip_have
    puts "You have enough IP, after buying #{champion_want}, you will have #{ip_have - value} remaining."
  end
else
  puts "We don't have a value for #{champion_want} at the moment, sorry."
end