Amazon is selling the Kindle Paperwhite for $79, which is a savings of $40. This deal is only available for Prime members based in the United States. The Paperwhite is also available in Canada for $99 for Prime members, but you can also see the discount once you initiate the checkout process.
The Paperwhite is likely the most popular e-Reader that Amazon is currently marketing. It has a backlit display, so you can read in the dark. If you borrow ebooks from the public library, the Kindle is the only e-reader that can have ebooks directly delivered to the device.