Field help (CPR) 

This is the unit amount by stock unit that can be used to value the stock (if the valuation method for a supplier receipt is Order price). The valuation method for the stock is defined by product category or by product category as a function of the storage site. It can also be set up by movement type.

It can be manually modified as needed, if the transaction authorizes it.
It can also be viewed on the Line cost window.

1/ Upon direct receipt:

Line stock cost / Quantity (in STK)

2/ Upon order receipt, the stock cost per unit is populated based on the value of the PRIFLG - Full stock valuation parameter (ACH chapter, REC group), as follows:

SEEWARNINGThis amount is never calculated during the entry process but only when saving the receipt.