As one of its daily deals, Amazon offers Prime members the Logitech M570 Wireless Trackball, model no. 910-001799, for $26.65 with free shipping. (Non-members can spend $35 or more to qualify for free shipping; otherwise, shipping costs $9.19.) That's a buck under our mention from last winter and the lowest total price we've seen for a new unit. (It's also a current low by $7.) Features include programmable buttons, 2.4GHz wireless, and up to 18 months of battery life. Deal ends today.