AnkerDirect via Amazon offers Prime members the Anker Wireless Vertical Ergonomic Mouse
, model no. AK-A7809012, for $12.99
with free shipping
. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping costs $8.35.) That's tied with our September mention and the lowest total price we've seen. (It's the best deal now by $8.) 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.