Fig.1 Buyer beware!

Have you come across this? Every so often a book is priced outrageously. Do some people actually buy at this price?! Is it an error? Is it a deliberate error that improves the ranking of an item or a seller on Amazon?

I've been buying ex-library books for 28p +P&P. 

Like old VHS cassettes there are books being 'dumped' - some are out of print gems that have not been digitised so you get to reference directly a book that has been cited rather than relying simply on what others have thought.