Not sure if this is just in the Liverpool One store, but could be nationwide as they get rid of stock, but HMV have a number of blu-rays for £3, some Special Editions..
Transformers 2: Revenge Of the Fallen including bonus digital copy (Bumblebee Transforming Case)
The Watchmen (Dr Manhatten Case)
Crazies (2010/1973): Bluray: Hmv Exclusive: Bonus Dvd Disc: Hmv Exclusive
Elvis: A John Carpenter Film: Hmv Exclusive
There was another one but I just can't remember what it was sorry guys...
Perhaps you will have similar deals in your local HMV Stores?