what states charge sales tax on web purchases?

Answer 1

Charging sales tax is an issue of the merchant, not necessarily the state. The merchant is required to collect sales tax if they have a presence in the state they are shipping to.

Answer 2

Any state that has a sales tax requires the tax to be paid on web purchases. If the merchant does not have a presence in the state to which the item is send, they are not required to collect the tax. In this case, the purchaser is responsible for paying the tax. The term 'use tax' is often used in this case. Ohio has a line on the state income tax form to declare use tax. I don't know about enforcement in any state.