Why is it that every taxable purchase made in a city or state with sales tax is taxed at the same rate? Why shouldnt the tax rate be lower as you make bigger purchases? so lets say in pa I buy a tv set that cost 1000 bucks, I pay six percent or 60 bucks in tax. I then go buy an f150 that cost fifty grand, and pay the same rate, six percent, why is that fair? why am i paying three grand in sales tax for that?