selling your wares

I am amazed at the number of online places to sell your wares. You no longer have to pay rent on a brick and mortar shop to sell your stuff. But how do they get the traffic necessary to get people to buy things? With the ten gazillion sites on the web, which one is better? which one will be "the one" to put you in business? If one chooses the wrong one, they lose money. Maybe a lot, maybe a little. but the intent in selling the things you make is to MAKE money not lose it. In some ways I am still in the dark ages. I just dont see how I can make money online selling stuff I make. Yet I cant see how to sell it at home in town either.