Absolute scam. It's essentially a competition, you just have to be around at the time when there's nobody else there with any bids to spend. Chances are, you'll never win anything. Avoid it like the plague!
Well after reading everything on here I did my own research and decided to give it a go anyway.
I won a Gourmet Society Membership card which gives me 50% off my meals at a host of restaurants. About five of which I use very often and live next door to. It cost me 1 pence. I also won 185 extra credits.
If you're sensible and realistic about how much it'll cost you it's not that bad a site.
If you decide to sign up and see for yourself please use my username 'Biscuit66' and I get extra credits.