Etekcity via Amazon offers its Etekcity Scroll 6E 4000 DPI Wired USB Optical Gaming Mouse, model no. 679113374270, for $18.99. Coupon code "BIGDEAL6" cuts it to $12.99. Plus, Prime members bag free shipping. (Non-members can spend $35 or more to bag free shipping; otherwise, shipping adds $8.64.) That's $56 off list and the lowest total price we could find. It features six programmable buttons, Omron micro switches, and five selectable sensitivity levels.