I got mine from Amazon.UK for less, even with shipping. If I was going to drop that much on a book again, I would get the one just about chelonian medicine.
Usefulness... I would say that the average keeper would be hard pressed to get the full value of the book. It IS NOT written for the non-vet and does not explain many terms or describe most of the actual procedures. I read it with the Internet up to help explain many of the concepts.