Photobox.co.uk have loads of offers all the time The code YOUR50 should get you a 50% discount too. I've just got some cards printed by them and they're really nice quality and came in 36 hours. Thumbs up from me.
NOT photobook - but Calendars - may be of interest to somebody.
www.vistaprint.co.uk/bb99 Wall calendars - 99p plus carriage Desk calendars - 39p plus carriage
At check-out you are offered multiple purchases at a special price, and, if I remember rightly, you are offered mulitple purchase for a second time at end of check out, with slightly better prices again!