I love eBay

Have bought a complete bike, frame, components, and many other things on eBay. I even bought a car on eBay once

All experiences have been very positive!
I haven't looked into the Fuji bikes, but I believe there are some members of the forum who have Fujis and are very happy with them.
The best thing to do is research the bike, make sure you know your sizing, decide how much the bike on eBay is worth to you before you start bidding, check out the seller's record, email them in advance if you have any questions. If everything is working out then bid with confidence!
Good Luck
Dax