A purchase order (PO)is a form of a contract and is a legal document used to place order for goods or services with a vendor. Clark Rents offers various heavy and construction equipment rentals in NY State.Find an equipment rental near you today. In this video I'm going to do the boring thing and show you exactly how to fill these documents out. THIS PURCHASE AND SALE AGREEMENT (this "Agreement") is made as of this ____ day of. A loan contingency clause in a contract defines a condition that must be met or an action that must be taken before a sales agreement becomes binding.