I've purchased three that were over $10, two of those were 2+ years ago.
Nowadays, with library loans and an abundance of lower priced quality books, it is an extremely rare book I'll pay over $10 for.
Also, Amazon has many sales for Kindle with Special Offers owners, that it is even more vanishingly slim.
Last, but not least, since I am an Amazon Prime Member, I can borrow one monthly from a huge list of books.
So much out there if one is patient and diligent in searching the legitimate sources.
However, I am sorely tempted to get 11/22/63 by Stephen King @ $14.99.
Dean