J-Tech via Amazon offers the J-Tech Digital Scroll Ergonomic USB Mouse
for $19.99. Coupon code "OBQAYG8O" drops it to $14.99
. Plus, Prime members bag free shipping
. (Non-members can spend $35 to bag free shipping; otherwise, it adds $8.64.) That's $5 off list and the lowest price we could find. It features up to 1600 dpi and forward/back browsing controls.