I don't think it's a scam <acronym title="to be honest">tbh</acronym>
They will make a significant loss on some items, but the bids cost you over £1 each pretty much
So if an Ipod nano RRP £99 say goes up, and 100 people bid on it, they have made money (so the price is above £1.01 on the item as it increases a penny each time), now add to that that you have fairly high postage on top it seems like if you are an opportunist and time it right you COULD get them cheap, but it's the timer resetting that got me, for the mini they had, went for £6.83, so they potentially lost £6k or so, but then you look at the cash deals, they made over £150 selling £50
£250 cash, £24 so they made £2400 in bids on £250
It's not a scam as such as you probably get your items (no guarantee as I have never used them) but it's very lucrative, just like those cash call shows late at night where you pay £1.50 or so just to stand a chance of getting through, even then no guarantee that you get through but you still pay, even if you dont win the item you still pay each time you bid on this.