For taxes, it sounds like GB would add the tax to the invoice and I'd need to make sure and give the buyer the total with tax. If they pay through money order I'd be responsible for getting the tax to their state but if I use guntab it sounds like they handle it if it's enabled on the account.
https://www.guntab.com/help/articles...ax-for-sellers
Of course I'd want to list that local sales tax will be added based on the shipping address. ;-)