Hi hairycarrot!
While I don't have a business license/tax ID for my own personal business, I do work for a small nonprofit and use our tax ID to purchase things at cost and tax free.
I believe to be tax exempt or to have tax exempt status, you have to be a nonprofit or an educator...unless a wholesaler specifies...but I could be wrong on that. If you do have an exemption, you'll receive a tax exempt ID from the IRS. When you go to make purchases, you just let the seller know that you are tax exempt. It's really quite easy.
If you are going to a wholesaler to purchase items and they require your business license, just simply provide them with that or let them know that you have one. Sometimes you do have to ask or let them know. It's really just as simple as that.
