Purchase and Sale Agreement. A purchase and sale agreement is a contract between a buyer and seller for transacting a property in exchange for a specific price.Get a comprehensive understanding of Texas real estate purchase and sale agreements with our indepth overview and free template. Streamline your real estate transactions in Texas with our customizable purchase agreement. Ensure legal compliance and purchase or sell properties. 1. Identify the buyer and seller in the agreement. A Sales and Purchase Agreement (SPA) is a legal contract that details the agreement's terms and conditions. PARTIES: The parties to this contract are. (Seller) and. (Buyer).