How is price picked in Purchase order?

Suggestion:
Price and the relevant details are picked from an indent, quotation or rate contract when these are respective sources for order creation. If the price list is found for the supplier and price list contains a price for the item, the Purchase Order retrieves the price from that price list. When it is directly ordered with or without any reference/source, System allows the user to enter the rate to be applied at the time of receipt.