A small business refers to any local shop in a locality serving the needs of individuals living in that locality by selling them the basic necessities of life. These business owners require to keep a record of their sales and this is done by keeping invoices of the sales. A small business sales invoice refers to any purchase of goods made by an individual from the business owner. It reflects the things purchased along with the quantity in which they are bought. The total cost of sales is calculated by adding up the prices of individual items sold from their store.