E-readers are a niche product but offer a superior reading experience to regular light-emitting displays, while also freeing you from notifications and battery constraints. While Kobo and Sony also make them, Amazon has the e-reader market mostly cornered. The current gen Kindle Paperwhite introduced audiobook support and waterproofing and is now on sale for $90.
It's been a few months since the Paperwhite was last discounted to $90, and the sale hadn't lasted too long. This is the 8GB variant with lock screen ads – which are quite unobtrusive and manageable. You can remove the ads for $20, and upgrade to 32GB storage for an additional $40 (worth considering if you will listen to a lot of audiobooks).
By adding waterproofing and Bluetooth audio playback, Amazon has made the Paperwhite a lot more versatile. In my opinion, it's now a better buy than both the cheaper 'all-new Kindle' (currently $70) and more expensive Oasis (currently $280) and Voyage models.
The sale is across retailers, and we saw the price on Amazon, Target (though it wasn't in stock at all stores), and Best Buy. Keep in mind though that Amazon sells the charger separately, so if you've already purged yourself of microUSB cables you'll need to get one again.