Hello Amanda,
Most states have a sales tax if you are in the US and Canada, but there are a couple that don't. If you reside in one of these states just let the wholesaler know and they may have a different form or requirement for you to complete. You will need a tax ID If you sell online to make money .
You need a seller's permit so you can charge and collect taxes, which you'll pay to your state government later. If you want to purchase goods wholesale from a US supplier (and you are also based in the US), you need a seller's permit to buy wholesale sales tax free.
It's always pretty important to ask your local government if you would need both a tax ID number and a business ID. Although it's not necessary for SaleHoo members to have a seller's permit and a registered business for them to use many of the suppliers in our directory, we strongly recommend you get one as it will give you access to even MORE wholesalers.
Hope this clarifies! :)