A business license will sure help, but you'll still run into some of the same snags. Some require a store front, some want pictures, most all have a minimum order requirement, and some just won't bother with you if you aren't spending a lot with them and/or you'll get a much higher price if you don't order cases of stuff. I've learned all this with a business license, with a shop, and with my number in the yellow pages.
That's just the way business is these days. "Mom and Pop" stores are practically extinct, and that is why--it's more profitable for the manufacturers to sell by the truck load instead of by the box. One of the few exceptions is truly hand-made items that can't be mass-produced by a machine--at least not with anywhere near the same quality--i.e. flemish strings, wood arrows, etc.