[What is a Sales Agreement?] Australian Sales Agreement. A Sales Agreement, similar to a Bill of Sale, is used to document a transaction of greater than $500 between a buyer and a seller. The Sales agreement can be used for anything, including assets, vehicles, and equipment. Types of purchase contracts. There are basically 2 types of contracts: purchase contract for the assets of a business (i.e. you purchase only specific assets that the business currently owns) purchase contract for shares in the business (i.e. you purchase all the shares in the business and, so, take over all its assets and liabilities). Contract of Sale of Business. Standard form of contract prescribed by the Estate Agents (Contracts) Regulations 2008. Warning: This is a binding contract. You should obtain the advice of a solicitor before you sign. By signing this contract, the Purchaser acknowledges that before signing this contract the Purchaser received, where appropriate: