You can do a lot to protect yourself from a bad ebay experience. I use the following rules for ebay:
a. Use Paypal.
b. Use your credit card when using Paypal (this gives you double protection).
c. Never send cash, check, money order or Western union when using ebay.
Also, I like to use Craigslist and I use the following rules:
a. Meet in public place.
b. Use or accept cash.
c. Don't accept or send checks, money orders or western union (CASH ONLY).
d. Don't send your merchandise to NIGERIA!
Using these methods will go a long way towards keeping you out of trouble. More ebay feedback is a more reliable indicator of having a good experience. You can still have a good experince from a low feedback ebayer.