A paean to charity shops.
Best of all though are the dedicated second hand charity bookshops. Admittedly, for the most part the fiction sections are usually full of intolerable trash, although I've still managed to pick up some Will Self from my local one. Where it continues to amaze me is in what it gets outside of the holiday reading cast-offs. Last time I paid a visit I picked up a first edition hardback of Roy Jenkins' biography of Churchill (complete with message inside from whomever gave it as a Christmas present), as well as Francis Wheen's Tom Driberg biog and have in the past got E.H. Carr's multi-volume history of early Soviet Russia, Bakunin on Anarchy, David McDuff's superb translations of both Crime and Punishment and the Brothers Karamazov and too many other great discoveries to list. Today's haul still must be one of the best yet:
The Prophet Armed - Trotsky 1879 - 1921 by Issac Deutscher (paperback) (also previously got his rather thin Stalin biog from the same place)
Michael Foot by Mervyn Jones (hardback)
As If by Blake Morrison (hardback)
The Gulag Archipelago - Second Volume by Solzhenitsyn (paperback) (got the first from the same place some time back, as well as the First Circle and One Day in the Life of...)
Kalki by Gore Vidal (paperback)
How much? £5.50 the lot. I also nearly picked up Peter Ackroyd's biog of Thomas More, but thought it'll probably still be there next time.
Every town deserves a similar shop, and for every dismal, run-down charity hovel attempting to sell mouldy boardgames, hornpipe trousers and flowery 70s shirts, there's one that's hosting a treasure trove, even if not one to you personally, just waiting to be discovered. Try it sometime.