The amount of money that changes hands in a purchase.
(=> (And (Currency-Transferred ?Buy ?Price) (Object-Sold ?Buy ?Prod)) (List-Price ?Prod ?Price)) (=> (And (List-Price ?Prod ?Price) (Object-Sold ?Buy ?Prod)) (Currency-Transferred ?Buy ?Price))
(=> (And (Currency-Transferred ?Buy ?Price) (Object-Sold ?Buy ?Prod)) (List-Price ?Prod ?Price)) (=> (And (List-Price ?Prod ?Price) (Object-Sold ?Buy ?Prod)) (Currency-Transferred ?Buy ?Price)) (=> (Currency-Transferred $X $Y) (Currency-Quantity $Y)) (=> (Currency-Transferred $X $Y) (Purchasing-Agreement $X))