The United States Government does not refund sales tax to foreign visitors. Sales tax charged in the U.S. is paid to individual states, not the Federal government – the same way that VAT is paid in many countries.
If you are making a major purchase, such as a car, and you intend to export the item, you should contact the state taxation authority in the state where you will be making the purchase. They will be able to inform you of their criteria for refunding any sales tax paid.
Source: cbp.gov
