Welcome, fellow Canadian!
As a mystery reader, you're kind of in luck, because if you check in our Deals, Freebies, and Resources forum, a lot of the time-limited freebies and promos the publishers offer tend to be for mystery books (as long as you like cozies and ex-cops turned PI and the occasional thriller).
Also, we've a very nice collection of mysteries in our very own
Patricia Clark Memorial e-Book Library, which are great if you like older classics like Dorothy Sayers and Dashiell Hammett, who happen to be public domain under Canada's Life+50 copyright laws.
Hope this helps, and happy reading!