Suppliers module

Hi to everyone, I am trying to build a new module for my suppliers so I can use this to quote my orders and track my expenses. The thing is that I have the product (A) which has the cost price of €150,00 and sale price of €180,00 but in Line items I cannot show the cost price, only the default which is the sale price. Since the product (A) is becoming from my supplier I need to see only the cost and then, after I create a new quote for my costumer I can see the sale price, which is correct. I really hope for an answer so I can start using it. Thanks.