I believe the book is out of print, and the prices you're seeing are therefore the prices set by used book dealers. Amazon doesn't have much control over what price a used bookseller asks for a title; they do act as a clearinghouse for many used booksellers to advertise their wares in one place.
Since Amazon in the US currently lists "2 new & used" in paperback and "3 new & used" in hardback, I'm guessing that Amazon has 0 new copies available. (They always have a "List Price/Price" section above the "new & used" prices if a book's available from their inventory.)
Out-of-print books can be a rip-off, but that's really up to the used booksellers, not Amazon. Once a book's out of print, sellers will get whatever they can for a book. In the US, at least, that can lead to some very strange pricing anomolies. I've seen books with a price spread from $5 to $100, all in similar condition. Sellers don't always know what they have, good or bad.
Be well.
Dave