The PDSA charity shop near the Norwich Bus Station has a table full of pooterbooks, new, but some of them admittedly have whiskers.
At first glance there's not a lot which is obviously for Linuxoi, (I've had those innit), but there are piles and piles of useful-looking books on the multitude of programming tools.
They've all been reduced from their oiginal prices to three squids, and from there to a pound, nicker, quid or oncer.