JemJem offers the refurbished 4th-generation Apple iPad 64GB WiFi Tablet with Retina Display in Black, model no. MD512LL/A, for $319 plus $1.99 for shipping. That's the lowest total price we could find for a refurb today by $99, although we saw it for $46 less in March. It comes with a non-OEM wall charger.
A 90-day JemJem warranty applies. Of note, new customers can use coupon code "VIP10" to take an extra $10 off.