Price lists are another required aspect for entering and transacting an order. Advanced Pricing is a separate product that Oracle licenses to businesses with complex pricing methodologies and mechanisms.
However, Basic Pricing can be used within Order Management without having to procure the Advanced Pricing product family.
A detailed comparison of the differences between Basic Pricing and Advanced Pricing is available in the Order Management Implementation Manual (Part No. E13406-04). All items that are transacted on an order must be on a price list. The price list must be the one that you chose for the order. The price list for the order is first captured on the Order Header, but can be changed for each line if needed.
You cannot change price list default pricing without defining discount rules.