No idea how much longer this sale will last, but
Currently as ebook on Amazon US for $2.90
Same, $2.90 Don't think it's the enchanced version, that's just the image that Booklikes has for the ebook.
[Reposting this again since I just saw the Book Thief sale. Also must give a hattip to the place I often find sales I can't resist, Dear Author blog's Daily Deals. This particular deal here. Humorously I saw the King sale and went off and didn't read the rest. Today I saw the Book Thief and tried to talk myself out of it and failed. Heh.]