E-Tech Galaxy via eBay offers the open-box Apple iPad mini 4 16GB WiFi Tablet in Space Gray, model no. MK6J2LL/A, for $299.22. In cart, it drops to $249.22. With free shipping, that's $110 under the lowest total price we could find for a new factory-sealed unit, although we saw it new for $24 less in November.
Note: No warranty info is provided.