Sales tax is a type of excise tax that is placed on goods and services in the United States. The payment of sales tax is unswervingly enforced by the state government, and paying this tax is mandatory if a person plans to do business in a particular state by buying and selling goods and services. Everyone must pay sales tax, and pay the same amount of it, no matter what their financial status may be. Sales tax is based on the price of the item that is purchased by an individual, and is collected from the buyer at the same time as the payment for the item purchased. Local and state sales tax is figured as a percentage of the cost of goods or services that someone buys.