Have just seen this for £10.85 at Zavvi, but with Walkers code it's £9.76!!! Link below.
Still in cinemas at the moment but available to pre order (available 14/2/2011) at a good price. Good reviews for this too.
IMDB score 7.8/10.
Paul is a U.S. contractor working in Iraq. After an attack by a group of Iraqis he wakes to find he is buried alive inside a coffin. With only a lighter and a cell phone it's a race against time to escape this claustrophobic death trap.