Amazon's latest entry-level Kindle currently costs $89.99, but for today only, there's a cheaper alternative. Woot is currently selling the previous-gen Kinde for just $49.99, a $50 savings from the original MSRP.
This model is as bare-bones as an e-reader can get: there's no backlight, and the 6-inch display has a relatively-low pixel density of 167 PPI. That means text won't be quite as crisp as it would be on a Kindle Paperwhite, but it's still perfectly readable. However, you can still read books from Amazon or your own ebook library (PDF, HTML, and other formats are supported), and the 6-inch e-ink screen means you don't have to worry about sunlight glare.
The sale is only live until the end of today, or whenever stock runs out.