Just an FYI, as my experience with this is limited and probably not all inclusive. First, understand that sales tax has nothing to do with income tax.
Generally when a supplier will only sell to an entity with an EIN, it's because that supplier is a licensed wholesaler who is not required to charge or collect sales tax. They usually have some type of documentation from the state or other lower level taxing authority allowing them to do this. They usually sell at a wholesale price to other retail businesses that will resell the product at a higher retail price. Then the retail business is required to collect a sales tax and pay that tax to the state or other taxing authority on a periodic basis - be it monthly or quarterly.
If you are purchasing products at a wholesale price for personal use and not paying your state or lower level taxing authority, then you "may" be in violation of some law or ordinance. This also puts the wholesaler at risk too. This may be something you want to check out to confirm beyond any doubt that you're not in violation of any laws or ordinances. Otherwise, if/when you're caught, the excuse of "I didn't know" won't fly. The fines/penalties can be (and usually are) very high.
