Was in HMV (oxford street) today as they have A LOT of cd's on offer for 2 for £10 and noticed at the entrance they were advertising that if you traded in your copy of modern warfare 2 they will knock the price of Dead Rising 2 from £40 to £20. Far as I could tell it was for PS3 and XBOX 360
Im going back down there tomorrow to get it myself, well worth it considering the new COD is out next month.
Bare in mind this is probably store specific and the store i visited was the HMV on oxford street, a few minutes from Topshop. They also had a giant man sized zombie statue outside advertising the game for sale (pic included) which was pretty cool.
Zombie Statue: http://img683.imageshack.us/img683/541/img00065201010061713.jpg