Anker Direct via Amazon offers Prime members the
Anker Wireless Vertical Ergonomic Optical Mouse for
$13.99 with
free shipping. That's a buck less than our May mention and the lowest price we could find by $3. It features a sensitivity adjustment button (800, 1,200, or 1,600 DPI); next page and last page side-buttons; and is compatible with Windows, Mac, and Linux. Two AAA batteries are required (not included).