I personally don't advise on purchasing anything over $100 on ebay.
Simple reason is that if ANYTHING is misrepresented, the chances of you getting a refund gets rapidly diminished.
I would advise a person-to-person listing such as craigslist so that you can verify the condition and functionality of the device before parting with your hard-earned money.
just my $0.02
Current: White iPhone 3GS, Curve 8310
Previous: 8900, iPhone 3G, 8300, 7290