Since many of us have non-Kindle ebook readers and with Calibre we can always take any ebook and strip the DRM and side-load it onto our devices, I think a platform-agnostic ebook bargain thread is needed.
To kick it off B&N is offering ten Ray Bradbury ebooks at $1.99 each:
If you want something for a Halloween mood, October Country or Something Wicked are tough to beat.
Also, Kobo has a silly trivia contest going where you can get codes for a percentage off an ebook. I say it's silly because you get to keep trying until you get the answer right and get the coupon. The coupons are good for 10%-75% off selected titles, but I find that they sometimes work on other titles too. Here's the link: