CowBoom offers the used 4th-generation Apple iPad 16GB WiFi Tablet with Retina Display in Black, model no. MD510LL/A, for $164.99. Coupon code "iPAD421816" cuts that to $114.99. With free shipping, that's $50 below our October mention of a used unit and the lowest total price we've seen for this model in any condition. (It's also $241 less than the best deal for a new unit.) Deal ends February 18.
Note: No warranty info is provided.