I first heard about eBay from someone I know who was using it to expand his buisiness beyond his store and into the wide wide world. That is definitely eBays biggest advantage: the fact that you can meet sellers and buyers from all over the world.
I first started out, like most people, by buying a few things on eBay. I quickly found myself snapping up deals on things I wouldnt have bought otherwise. However, I also scored a really great gift that I could never have found anywhere else. eBay simply has everything! Somebody, somewhere in the world has what you are looking for. And chances are, they listed on eBay. If they didnt, dont worry, it will be there next week!
After a few weeks, I decided to try my hand at selling a few things on eBay. I quickly researched similar items on the site to find out what kind of price I could ask and then started a few auctions. So far, things are going rather well. Ive made myself a little profit and havent met any deadbeat bidders (who dont pay) or sellers (who send you a bad item, or nothing at all).
I would recommend you try out eBay for yourself. But control yourself, and dont buy everything on the site!