$3.49 (£2.16) for code from Amazon US
£4.49 on UK Playstation Store.
This code is for American Playstation Store, but a lot of people don't realise that PS3 consoles are not region locked with their content.
To play this game on a UK PS3 you just buy this code, go to Users tab on the XMB, create a new user, then sign up for an american PSN account on that new user. You can then get all the american content (most of which comes out before the UK).