There are many more supermarkets came into existence in the USA during the great depression of the forties. however, the original supermarkets were established by independent merchants who deal with many more heterogeneous commodities to achieve the business objective. the customers are deals with the shopping themselves from the racks which are properly labeled and at the end of the shopping, there is the cashier who takes the cash after weighing and checking the commodities. usually, the customers make their purchases and carry them in trolleys. thus the supermarkets are also known as self-service stores since the customers are to do all the purchasing by themselves without any selling assistants.