As an eBayer with over 100 xactions under my belt, I can offer up to be wary of sellers with very low or no feedback. Also look at the bidding history. If there are a lot of bids by 0 feedback user id's, the seller may very well be bidding on his own stuff to help move the price up! (against e-bay rules, but it is still done).
Also some companies that do buisness there can be very slow on giving you feedback. I have had several that took between 1 - 2 1/2 months to give feedback!
Also use different terms to search for your intrests as sellers may list it differently then you are searching for. (radio Vs stereo for example)
After your inital search, you can check a box that has eBay also search the body of the item's text, not just the header. (but you can also get overwhealmed with garbage too!)
Also sometimes things just don't go right. Earlier this month I purchased a Ford AM/FM Cassette W/6 disc changer. Due to problems on the sellers side (death in the family, friend said he would ship it, but didn't), it took almost 3 weeks to complete a transaction that should have taken 5 days. (turns out the seller is also a F150online member)
Fortunatly so far, I have yet to be ripped off (never getting what I paid for), but there have been a few close ones.
One other thing, you can get items cheaper there then you can in the store, but you may have a problem with the MFG honoring the warranty due to you not having a store reciept.
I had to fight HP to fix a new in box scanner I purchased. They finally agreed to honor the warranty from date of MFG, not of purchase!
I had the same problem with a camera. Ended up purchasing the same camera from a chain store, made a copy of the reciept & then returned the one from eBay. So now if I need warranty work, I do have a copy of a valid store receipt!
