Okla. Stat. tit. 68, § 2104

A. The value of any motor vehicle, except a manufactured home, for the purposes of the excise tax levied by Section 2103 of this title, shall be determined as of the time the person applying for a certificate of title thereto obtained either ownership or possession of the vehicle, which shall be presumed to be the actual date of the sale or other transfer of ownership, and assignment of the certificate of title. B. The value of any vehicle, for purposes of the excise tax levied by Section 2103 of this title, shall be the actual sales price of such a vehicle. The actual sales price of the vehicle, which total shall be the basis of the motor vehicle excise tax, as well as the number of tires on the vehicle and the tire rim diameters, shall be entered on the bill of sale furnished by the seller to the purchaser, or on such other form as may be prescribed by Service Oklahoma. Upon receipt of the properly completed bill of sale or other form as prescribed by Service Oklahoma, and the payment of all applicable taxes and fees, Service Oklahoma or an appointed licensed operator shall issue a vehicle certificate of title in accordance with the provisions of the Oklahoma Vehicle License and Registration Act.