FD Tech via Amazon offers its FD i887 6-Button Wireless Vertical Optical Mouse in Black or Gray/White for $22.99. Coupon code "I88740OFF" cuts that to $13.79. Plus, Prime members bag free shipping. That's the lowest price we could find by $3. It features three DPI settings (800, 1,200, and 1,600) and a 2.4GHz nano receiver. One AA battery is required, included. Deal ends August 23.