The Hobbit: Desolation of Smaug Blu-Ray [3D + Blu-ray + UV copy]
I've been keeping tabs on this one for a while. Best new price has been £17.00 and used copies have been going for near enough the same.
£12.14 + £1.26 delivery from Pandagames
Also in case they run out a competitor on Amazon Marketplace has it for a penny more.
Edit: Pandagames copies gone, Revival Books Ltd stock left
Edit 2: Sold out, guess it really was a cold deal *shrug*