As @bookmarked mentions above, it's probably worth taking a look at the Simon & Schuster sale on right now, with lots of titles going free and also at $0.99 and $1.99 (including the Frank Kane and Robert Barnard ones I mentioned a few posts up).
So far I've noticed titles by: D.C. Brod, Nancy Pickard, Loren D. Estleman, Randall Peffer, and others. I'll come back and add more later.
You can use the link in @bookmarked's post to get to the thread for the sale, and then
my post near the bottom of the first page gives some hints for how to narrow down the various searches just for mysteries (and some other genres too).
EDIT: A few other authors I recognize: Stephen Greenleaf, Stuart Kaminsky, Mary Logue, V.C. Andrews. Some have a freebie or two, some have $0.99 or $1.99 titles.