I have no idea why -- it's nothing I did -- but The Seven Markets seems to be "on sale" at Amazon right now for $8.29. I suspect it's because they're matching a low price someone out there (Barnes & Noble, for instance) is selling the book for. Or maybe they had too much whiskey with lunch. I don't know. I've heard about this sort of thing happening with ebooks, where Amazon will suddenly discount you to match another vendor's pricing. But the ebook isn't for sale anywhere else.
At any rate, it's on sale. Discounted. Something. It's very strange and I have no idea how this will affect my royalties, but as I didn't do it I don't think there's anything I can do to change it. So, if you were holding out for a paperback copy of the book and want to save a few bucks, go for it.
Very, very strange.