Commercial and Investment Real Estate Purchase and Sale Agreement. Already A Commercial Contracts Pro Subscriber?A long form agreement for the purchase and sale of commercial real property in Illinois. Seller shall also furnish Purchaser with: (i) an Affidavit of Title in customary form; (ii) a Bill of. An Illinois commercial real estate purchase and sale agreement contains the key terms and conditions of a commercial property transaction. Make the steps below to fill out CONTRACT TO PURCHASE COMMERCIAL REAL ESTATE - MLS online easily and quickly. This form of purchase and sale agreement includes guidance for both purchasers and sellers in Illinois commercial real estate acquisition and sale transactions.