You are right everything is the same price no matter who buys it (except online), but there is a fair amount of complexity to sales tax. Dine in food might be taxed, but take out food is exempt in some states. In my state, bottled coffee is taxed if it is sweetened, but not if it unsweetened. Bakery goods are tax free, unless plates are made available then it is taxable. Sparkling water is not taxable, but sparkling water with fruit flavor is taxable, unless it has 50% juice, then it is non-tax again.