Visited yesterday and I couldn't figure out how to use it at first. Then I read the text on the left (doh) and I got 40 pictures printed for peanuts. Paid only for the postage, so it worked out £0.10 per picture, cheapest printing I've ever done.
This site claims to offer you free photo prints but it actually lists special offers everywhere else also you do have to pay postage on the prints. Anyway it is a helpful site as saved me looking for prints everywhere else. I emailed the site owners to ask about postage costs and they were quite helpful. Overall a nice site just wish they listed postage costs next to each 'free offers', its a bit like Vistaprint - great offers just wish the postage was clear.