As one of its daily deals, CowBoom offers the used Microsoft Xbox One Day One Edition Console, model no. 7UV-00077, for $329.99 with free shipping. That's $20 under our July mention of a used console and the best price we've seen for this console in any condition. (It's currently $30 under the cost of a new one.) It features 500GB hard drive, Kinect Sensor, cable and satellite box pass-though so you can watch live TV from your console, and Blu-ray player. Deal ends today.
Update: Note that it doesn't include a wireless controller or a chat headset.