A whole load of DVDs on a section called "DVD Blitz from £3" is on at Sainsburys. Am pretty sure its instore in the main stores.
I saw a lot of other newish films like Slumdog Millionaire, The Wrestler, Valkyrie, The Proposal and many more ranging from £3-5
Personally I got:
The Dark Knight (2 disc edition) £4
The Wrestler £4.99
The Kingdom £3
Hope this helps someone, just to say its well worth a look.