I use eBay as the main source for all my equipment.
I bought my 5D with 24-105 for £1400 three years ago when they were typically £1800-1900. The seller looked dodgy as hell with only about +10 feedback and none of his previous sales had anything to do with photography.
I didn't actually win the auction, but the highest bidder pulled out because the item location was described as Yorkshire when in fact it was Essex, so I received a second chance offer. I accepted the offer and drove up to him with my girlfriend in tow and the cash in an envelope which was a bit scary in itself. I rung the bloke when I was outside his house as I couldn't find any parking and he came out with a carrier bag and jumped into the back of my car. It was a boxed, unused kit with the factory seals intact. After giving it a quick once over, I handed over the envelope containing the cash. He got out without even checking it saying he trusted me.
I bought my 70-200 f/2.8 IS for £700 from another bloke in Essex. This was a bit less suspect as his previous and current auctions had connections to wildlife photography, but he was a film user so his listing had no images of the lens itself. Again, it was a case of driving up with the cash. A funny thing I remember about that was an old Jaguar XJS with a
for sale sign parked outside his house which was cheaper than the lens I was about to buy.
Most recently, I found someone who had no idea about photography but had come into owning about a dozen white boxed 24-105L so they were all listed identically as "Canon lens" and a single line of description. At that time, they'd received +ve feedback for a single lens which they'd sold up until then so I took a chance. I won one of those for £450 and stressed like hell when it hadn't turned up when expected. It turned out it was entirely the Royal Mail's fault as it coincided with terrible weather or a strike and ended up sat in the local depot without anyone making an attempt at delivery after a week. It was only when I phoned the depot and a helpful lady went to look for the parcel was it found and my bum twitching ceased.
If you want to find a bargain on eBay, they're there but you need to be prepared to put in the leg work and possibly take a calculated risk.
