Spotted this in my local HMV (Merry Hill) yesterday. I didn't buy as I already own a copy of this classic though I asked at the counter and the deal is nationwide.
Also available was Zombie : An Anthology of the Undead by Christopher Golden for £2.00
Sense and Sensibility and Sea Monsters by Jane Austen & Ben Winters for £2.00
A Scanner Darkly - Philip. K. Dick
Substance D - otherwise known as Death - is the most dangerous drug ever to find its way on to the black market. It destroys the links between the brain's two hemispheres, leading first to disorentation and then to complete and irreversible brain damage. Bob Arctor, undercover narcotics agent, is trying to find a lead to the source of supply, but to pass as an addict he must become a user, and soon, without knowing what is happening to him, he is as dependent as any of the addicts he is monitoring.