Meritline offers the refurbished Logitech M570 Wireless Trackball, model no. 910-001799, for $32.99. Coupon code "MLCKQ14SNL1" cuts it to $27.99. With free shipping, that's $2 below our May mention and $7 under the lowest total price we could find for a refurb elsewhere. Features include programmable buttons, USB 2.0 receiver, 2.4GHz wireless, and up to 18 months of battery life. Coupon expires after 100 uses.

Note: No warranty information is provided.