You can save a few bucks on - clothing, $100 or less - school/art supplies, $100 or less - computers, $1500 or less Sales tax is approximately 9%, depending on the county in which you make the purchase. http://tennessee.gov/revenue/salestaxholiday/
These things aren't worth the hassle. I can get better deals + free shipping - tax online... Not going to fight thousands to save 2 dollars on a shirt. Unless you're getting a computer or something, there's really not much to go out for.