The folks at Amazon are having one of their daily Gold Box Specials, making a number of mysteries available for 99-cents for the Kindle. Here's the information. The books are readable on the Kindle, of course, and on any number of free apps which you can download to read Kindle books on other readers, such as iPads and regular computers.
And, yes, if you get one of these, I get a few cents. I promise not to spend it all in one place. Sheesh.
Anyway, these deals are for today (Sunday) only.