My suggestion don’t wait until that week to do your shopping. Last year I kept an eye on sales and the sales tax and found that the sales aren’t nearly as good the week that sales tax is free. So unless you plan on doing all your shopping at Walmart where there are never any sales start looking now. Florida has capped school supply purchases at $10 per item so if you see a good deal on a backpack buy it now don’t wait it probably won’t be included.
I don’t have any numbers on clothes for you but last year I know that I bought a few things for Shawn at Target and JCPenney’s for 20-50% off and when the tax holiday came the sales were off, the stores were crowded, the selection stunk and you were only saving 7%. As far as school supplies I’ve already crossed a few things of Shawn’s list at a much better savings than 7% I have copy paper that I paid .01 for, scissors that cost a quarter, folders that were .01 each and dry erase markers that cost me only tax.
So don’t wait get out there and start plucking away at that list and check your state specifics for things you are planning on waiting on. If I’d waited to buy Shawn’s backpack I would have found that it probably wasn’t included (it was $13.99), I might not have gotten his lunchbox free with it (Toys R Us promo on now) and I most certainly wouldn’t have gotten the bag he wanted since the selection only gets slimmer. If you feel you must wait remember what your tax rate is and take that into account when you pass up a 20% or better sale.