Poisoned Pen Press now has a new bunch of $0.99 mysteries up for March:
http://www.poisonedpenpress.com/discover-mystery/
I haven't checked (have to run off to work so I can pay for all of my e-books
) but I assume these are the first, or at least early, in their respective series as PPP has done before.
As an aside (a recommendation, not a deal) I also just noticed that PPP has the two most recent Joanne Dobson/Karen Pelletier mysteries:
The Maltese Manuscript and
Death Without Tenure. I was lucky enough to get three of the first four in this series from Fictionwise before they imploded, and now here are the most recent two. I like this academic-setting series, probably because my dad was a college professor, and so the academic maneuvering Dobson puts in the books brings back memories - although it never got as far as murder at my dad's school, of course! Although you can get them a bit cheaper at Kobo (with coupon) or Amazon, I like buying direct from PPP because you get two formats DRM-free, and also because that way presumably both PPP and the author get a bit more money.