Consistent with this approach, we have explained that when the lease requires payment of the "market value" of the gas this value "means the gas purchase contract price." Helmerich Payne, Inc. v. State ex rel. Commissioners of the Land Office, 1997 OK 30, ΒΆ 12, 935 P.2d 1179, 1181. But when certain circumstances are present this definition of "gross receipts," as being a value with no deductions, has been tied to the value of the product at a certain location, that is, the leased premises, or wellhead.