Buying items wholesale
In order to purchase items in wholesale, you would have to obtain a state sales tax vendor identification number, often referred to as a reseller's permit. If you live or are conducting your business in Alaska, Delaware, Montana, New Hampshire, or Oregon, you would not need to have this as state does not charge tax on purchased goods.
Keep in mind that you are required to resell most of the inventory you buy wholesale (thats why its called "reseller permit"). Details vary from state to state.