The retail supply chain generally consists of four players: manufacturers who produce the goods, wholesalers or distributors who buy from manufacturers and resell to retailers, and retailers who buy from wholesalers and then sell to consumers. At each step in the chain there is a markup, or profit margin, built in to the purchase. Manufacturers calculate their cost of making a product and then add on a profit percentage before selling to wholesalers. Wholesalers do the same thing, adding a profit percentage to what they paid for the products. And retailers add their own profit margin to the cost of the product before selling it to their end customer, the user.

Retailing is the distribution process of a retailer obtaining goods or services and selling them to customers for use. This process is explained through the supply chain.
To complete a sale, retail stores have traditionally had customers bring their purchases to a cash register, where a clerk tallies the total cost and rings up the sale. Today, some supermarkets have self-check-out lanes, where customers can scan their items and check out using a credit card or cash. Customers buying online shop on their computer screens, click to select the products they want, and then type in their credit card information to complete the sale.