Some states in the USA even have a "use tax" because of Internet sales. In my state Apple and other large businesses have a physical presence and are required to charge tax on any sale made to somebody in this state. A use tax takes this a step further and even if somebody doesn't charge you tax, you are supposed to fill out a form come tax time and pay tax on anything you bought outside the state and pay the difference between that state's tax charged and what you would have paid here. So if I went to a state charging 5% tax and bought a candy bar for $1, I would be expected to pay $1 x (8% (local tax here)-5%) or 3c tax along with income taxes. It's a bit more complicated than that but you get how it works.