If you want a store, forget Brick and Mortar. Start on ebay, and move on to online websites (possibly through Yahoo).
I totally agree with this. Get your feet wet on ebay, Amazon, yahoo auctions and stores. All you really need for that is a cabinet, a scale, computer, postage supplies, and the werewithal to drive everywhere and find some rare stuff. That's what my husband and I do as a side business. His friend got us into it, and when his job was phased out, he was able to do it full time. He now has a tax id number and everything.