I got a 19" monitor for $50, and after selling it on Ebay for $100, I barely made a profit (Ebay fees, paypal fees). On top of the percentage Ebay took out, they charged me like $10 two weeks later for "seller fees".
Forget Ebay, Im going with craigslist or something. Another place that I havent really had a chance to check out all the way is glyde.com