A master purchase agreement is a legally binding contract between buyer and seller, and typically relates to buying and selling goods rather than services. A purchase and sale agreement is used to document the parties' intentions and the terms they have agreed will govern the transaction.Seller may own in the Collection. WHEREAS, Principal Underwriter proposes to compensate Broker for such sales and servicing;. The SPA must clearly identify the buyer and the seller, including their names, addresses, and any other necessary contact information. 2. Assets. May extend beyond the Termination Date. 2. Sale of Advertising Space. For a sample pro-seller master sale of goods agreement, see Standard Document,. The buyer then fills out the order form with their specific needs and returns it to the seller.