Newegg offers the refurbished Logitech K830 Wireless Backlit Keyboard with TouchPad, model no. 920-006081, for $59.99. Coupon code "EMCARKV65" drops it to $49.99. With free shipping, that's $10 under our mention of a new one from January and the lowest total price we've seen in any condition. (It's current low by $10.) It charges via USB and features a 33-foot range, backlit keys, and 10-day battery-life on a full charge (based on typing two hours per day with backlight at full brightness).
Note: A 90-day warranty is provided, but it's unclear who backs it.