I have seen some insane bargains on eBay over the last few weeks. I even had to watch one go by: a 30 back Imperial Hoth Trooper in really nice condition for less than £400. It was worth twice that easily. The reason I had to let it go was because I've also been lucky enough to pick up some absolute bargains, too, so I'm all spent up. Again.
I stand by that eBay is a GREAT place to buy and sell. I hate the company (they're utter dicks) and I hate a lot of the buyers and sellers (as per previous comment) but if you are careful then you will do well from it. The golden rule is to check the description: what's written there is gospel when it comes to disputes. If you need to have an argument with eBay because of a bad seller they will always revert to the description: it almost doesn't matter what the photo shows.