If you happen to like international mysteries, Amazon's exclusive AmazonCrossing translation imprint has a slew of their mystery/crime/thriller authors on sale, probably good through the month, available in Canada & the US:
@ 99 cents:
- Rain Girl & Raven Sisters, #1 & #2 in prize-winning Austrian author Gabi Kreslehner's (Wikipedia DE) Franza Oberwieser series starring a homicide detective in Munich
- Swimming in Sharks by bestselling German author Nele Neuhaus (Wikipedia), a thriller set in Wall Street
- Escape by prize-winning Turkish author Perihan Mağden (Wikipedia), a standalone psychogical thriller centred around a family that moves mysteriously from place to place for reasons yet to be revealed
- Stormy Cove by Swiss author Bernadette Calonego, an unsolved murder mystery set in Vancouver, BC
@ $1.50, which is a new sale price point for AmazonCrossing (usually the spread is between 99 cents, $1.99, and then $3.99):
- #1-3 in Finnish author Leena Lehtolainen's (Wikipedia) The Bodyguard series starring female bodyguard Hilja. I'm just going to link you to her author listing sorted by price, where #1-6 of her rather good and recommended Maria Kallio series of police procedural mysteries are also going for $1.99. I've read most of the available translated volumes in both these series, and while I enjoyed the Maria Kallio ones more, they're all reasonably solid cases. The Bodyguard series is more thriller-ish than mystery and has more in the way of f/m romantic subplot and action sequences.
- The Flatey Enigma by Icelandic author Viktor Arnar Ingólfsson (Wikipedia), a standalone mystery involving Icelandic saga elements surrounding a mysterious manuscript with a bit of a code attached if you happen to like figuring those out. I bought this a while ago but haven't finished it, but the story so far is pretty interesting (and I've quite enjoyed his other AmazonCrossing books that I've read).
- Pathological by award-winning Chinese author Wang Jinkang, a standalone biological technothriller
@ $1.99:
- To Clear the Air by German author Mechtild Borrmann (Wikipedia), an apparently standalone murder investigation which won her the 2012 Deutscher Krimi Preis.
- The Missing by Swedish author Caroline Eriksson (Wikipedia SV), a standalone psychological thriller centred around the eerie vanishing of two family members in the wilderness, and the increasingly desperate investigation by the one left behind
There are also a bunch of other sale titles from AmazonCrossing authors, who aren't quite as known in their home countries/abroad or didn't have particularly mystery-looking titles:
linkage for the lot sorted by price.