If the business you are buying includes business assets such as furniture or office equipment, you must pay sales tax on them. An APA spells out the conditions and terms under which a seller will transfer all of the assets that belong to the business to a buyer.Thus, both the Buyer and Seller must complete this application. Only businesses that are already licensed to operate a trade waste business in New York City may. A seller must give all prospective purchasers Form TP153, Notice to Prospective Purchasers of a Business or Business Assets. An asset purchase involves buying the sum of the company's assets, which may include buildings, inventory, equipment, or vehicles. An asset purchase requires the sale of individual assets. A share purchase requires the purchase of 100 percent of the shares of a company. A sales agreement for buying a business is necessary for keeping both the parties on the same page and avoiding any legal trouble.