Build-Buy is a group buying platform for construction companies that negotiates better deals with materials suppliers by leveraging the combined purchasing power of its members. It offers suppliers new customers, increased spending from existing customers through continuous repeat business, promotion on its site, and customer support. In return, suppliers provide Build-Buy with a reduced price list for members, a 2% rebate on new customer spending, and copies of customer invoices monthly. The process is designed to be simple, beneficial for both buyers and suppliers.