Introduction: Why Sales Tax Matters in the USA Sales Tax by State in USA 2026, If you’ve ever walked into a store in the U.S. and noticed that the price on the tag isn’t the final amount you pay at the register, you’ve already encountered sales tax. Unlike some countries where taxes are included in the price tag, the United States adds sales tax at checkout. Here’s the catch: sales tax isn’t the same across the country. Each state sets its own rules, some even letting cities and counties add more on top. That’s why buying the same $100 item in one state can cost $106 while in another it…