NYC Tax??!

Do you live in NY? If you don't, and there isn't a MJ store in your state, you shouldn't be charged any tax. Otherwise I would suggest you call the store and inquire about the tax rate.
I definitely know that the rules are if there isn't a physical location of the store in the state you live in, they are not supposed to charge you sales tax. However, you might want to bring that up if you are ordering something. I'm not suggesting that MJ SAs are not trained, but there are SAs in general who don't know that, or simply don't know (or not trained) to change tax codes in the computer/register system.