I am wondering what types of legal documents are needed if I want buy products (such as beverages, nonperscription medicine, snacks, etc.) from commercial wholesalers (such as Costco), and then re-sell them independently to consumers. Is this allowed at all, or is it completely illegal?.--Answer1:You need a local business license and a state tax number in most states. You can also apply for federal EIN number, which cost nothing and is usually the number businesses want when they say "tax number".