Xteink X4 Pocket E-Ink Reader

$69

A 4.3-inch E-Ink reader that weighs 2.72 oz and is thinner than a pencil — stick it to the back of your phone with the included MagSafe ring. Physical page-turn buttons, 16GB storage, and a 14-day battery. Best of all it's hackable: the community Crosspoint firmware turns it into an open EPUB reader with WiFi book pushes.