An attorney's explanation of an Office Purchase and Sales Agreement and its free template for commercial real estate. Use a commercial real estate purchase agreement to secure transactions and protect your interests effectively.I want to show you how to do this simple contract there is a simple contract in transaction desk that you can use for a commercial deal. The PSA is a map of the entire buying and selling process that creates timelines and responsibilities and offers buyer and seller protection. An attorney's explanation of an Industrial Purchase and Sales Agreement, along with template for industrial PSA in commercial real estate.