The Essential Harlem Detectives collects four books in the Grave Digger Jones/Coffin Ed Johnson by Chester Himes in one e-volume, and that volume is on sale right now in the US for $1.99. Which is a great deal even if you only need one or two of the books! The included books are: A Rage in Harlem (#1), The Real Cool Killers (#2), The Crazy Kill (#3), and Cotton Comes to Harlem (#7).
And my thanks to @ZodWallop at the MobileRead forums, whose post alerted me to this deal.