I buy and sell things regulary on eBay, although it's never been a real "business" type thing to me. I find locally I can only get a couple bucks trade in anymore on discs, and I usually average $7 or so on eBay, often way more for rarities and collectables. Mundane stuff I tend to trade locally cause it isn't worth spending time scanning and entering the info to pocket 2 bucks!
I've picked up some great CD and songbook bargains there too. Half.com is also okay for listing stuff- they often have a listing for what you're trying to sell and you just list your asking price and brief info- much quicker, but I have also had things sit there for months whereas an ebay auction you define how long it lasts for. One other piece of advice, make sure you have the auction active over the weekend. BTW, can't you also do a Mudcat auction that partly benefits the web site?

jim