In reply to hebes:
Price depends on which edition you want. Go to abebooks and search second hand books for avon and cheddar. I have just looked and there is at least one copy of the 1992 two volume set at £12 plus p&p. If you prefer the 2004 edition then start saving your pocket money as they are ridiculously expensive, wish I hadn't given mine away!
For the most up to date guides, Avon (£25) and Cheddar (£20). Both are listed as in stock.