An "Agreement for Sale" is your promise note it says yep, I'll sell this thing to you, but later. Agreement to Sell and Purchase.The document is an agreement for the sale of land with a down payment between Manuel King Q. Gaerlan and Angelita P. Valdriz-Gonzales. Seller shall sell and convey and Purchaser shall purchase the property, together with all buildings and improvements thereon (collectively the. The UCC "fills in the gaps," providing controlling contract terms where the contracting merchants either didn't agree or just forgot to discuss the matter.