What I do know is that not everyone is participating. In particular, Jefferson County is not! The towns/cities may be, so you won't have to pay the city tax, and the state tax has been waved everywhere, but the county tax would still have to be paid.
Shelby County (which is where I live) IS participating. So that means everything that qualifies that is purchased here will be tax-free. This also means that lots of folks from Jefferson County are down here shopping this weekend. It's a wee bit nuts.
But if you do need anything, now is a good time to get it, even if you do have to work on a little bit of patience. Just remember, parking in the back and walking is good for you. I doesn't hurt you to stand in line and wait. And just because someone is mean or rude to you, that does not mean you have to be mean or rude back!