I found a first edition hardback of Knight of Madness (short stories by various authors including Terry Pratchett's 'Hollywood Chickens'). That was £3 - more than I'd normally pay for a second hand book, but well worth it.
I also found 'Notes From a Small Island' by Bill Bryson for £1. I've never read any of his books, but lots of people have recommended him, so I'll give it a go.
“Men never commit evil so fully and joyfully as when they do it for religious convictions.” – Blaise Pascal