Kindle Daily Deal today has the whole "Nightingale" trilogy from Stephen Leather at $1.99 each.
Know nothing about them, but I've at least heard of this author and I thought at this price I'd dive in:
Amazon (US)
They also have Whispersync for Voice advertised for $1.99, but only the third book seems to have a valid link to a $1.99 offering at the Audible site. Not sure what that's all about, but I know very little about this service so maybe I'm doing it wrong.