Purchase prices from the different vendors can be stored in the Price List functionality.
However, prices can fluctuate and items can be purchased from vendors for which no Price List has ben setup.
The field "Last Direct Cost" on the Item card is therefore not always reliable.

It is requested to have a (general) option where the customer can choose to use the value in Last Direct Cost as purchase price in the purchase order or to leave it blank in case the item hasn't been found in a price list.