Are you talking about the price of the item?
You can setup item price in a simple way-putting the cost in the market price field located in the purchasing tab in the ITEM MASTER form
Here are some good notes on the subject of pricing with the steps involved on MY ORACLE SUPPORT:
- Vision Demo - Explaining and Illustrating the Setups for Default Pricing on Requistions, Purchase Order Items and the Autocreate Form (Doc ID 2332541.1)
- Advanced Pricing Utilizing Surcharges see Note 1101067.1 Vision Demo - How To Utilize Advanced Pricing in Purchasing
- How CREATEPO Workflow picks prices see Note 2333325.1 Vision Demo - Explaining and Illustrating the Pricing Utilized on PO's created by the CREATEPO Workflow When Requistiions Lines Have Different Prices
- Modifying the standard price see Note 2333317.1 Vision Demo - Utilizing the PO_CUSTOM_PRICE Public Package for Overriding Source Document Price With Requisition Price