Northwest Outdoor via eBay offers the open-box FitBit One Wireless Activity + Sleep Tracker in Black or Burgundy, model no. FB103, for $54.99 with free shipping. That's $20 under our Black Friday mention of a sealed model and the lowest total price we've seen in any condition. (It's $25 under a new one today.) One of the original wearable activity trackers, the FitBit One tracks calories burned, steps taken, distance walked, and stairs climbed. It also tracks sleep, and it feeds all of that data into your smartphone or laptop via Bluetooth.

A 90-day warranty applies, but it's unclear who backs it.