Vehicles are required to be titled in the buyer's name within 30 days from the date of sale. A vehicle sales agreement is a lawful arrangement summarizing the terms and conditions of a vehicle sale between a customer and a seller.Standard presumptive value (SPV) is used to calculate sales tax on private-party sales of all types of used motor vehicles purchased in Texas. A master purchase agreement is a legally binding contract between buyer and seller, and typically relates to buying and selling goods rather than services. Sale of Goods Agreement (Pro-Buyer, Short Form) (TX). (Pro-Buyer) (5-541-6567). Unless otherwise stated specifically in a Purchase Order, this Agreement shall apply to any and all transactions between Buyer and Company. 1. Definitions. The provisions of the sales agreement material to these controverted items are set out below in the margin. Pack your vehicle with all the trip essentials and drive it out of the station upon arrival.