Learn how to wholesale real estate in Illinois using this step-by-step guide. A wholesale agreement is a contract that transfers the ownership of goods from an original seller to the buyer through an intermediary, called the wholesaler.Learn how to wholesale real estate in Illinois: 1. Today's video is focusing on the paperwork specifically the assignment agreement between you and your cash buyer. An Illinois purchase agreement is a standard contract for selling real estate from one party to another. Chicago Association of Realtors – PDF. Check out our wholesale contract selection for the very best in unique or custom, handmade pieces from our templates shops. The best thing to do is to print out both the assignment contract and the purchase agreement.