I bid and bought a brand new Iphone from ebay India. Seller had 100% feedback. The phone worked well on the evening of Day 1 which was spent mostly in one corner of the house where the computer was located. Next day, I realised that it had weak reception and I was getting signal only in that area in my house. Called seller, he encouraged me to do a restore (reinstall O/S), learnt something new. This did not work and he asked me to send it back to him. He checked it and told me that even the earlier phone was working fine after he restored the O/S, but he gave me an option to either take the same or a new one. I chose a new one for peace of mind. I received the replacement within 2 days after that and it works like a charm. Communication with this seller further established the fact that people really care for their feedback/ratings on ebay.
Through ebay, I have been able to buy several things I could never have afforded. But yeah, it is not for the faint hearted and definitely not for the skeptical lot.