the Good-Service-or-Money that is agreed to be exchanged by the Sale-Vendor with the Actual-Customer in a Sale.
(<=> (Product ?X) (Or (Exists (?Sale) (Product-Sold ?Sale ?X)) (Exists (?For-Sale) (Product-For-Sale ?For-Sale ?X)) (Exists (?Potential-Sale) (Potential-Product ?Potential-Sale ?X))))