Use a California business purchase agreement to record the sale of a business. Download your free template today.This document is a business purchase agreement between two entities. It details the sale of a business from the Seller to the Buyer. This Agreement for Purchase and Sale of Real Property and Escrow. This article discusses seven (7) types of seller liabilities that should concern a buyer when negotiating the purchase of a California business. A business purchase agreement is a legal contract specifying terms for buying or selling a business, including conditions and obligations. The formal agreement which documents the sale of stock to the founders of a California corporation. 1.1 Purchase and Sale.