Also available is the factory-refurbished Apple iPad Air 32GB WiFi Tablet in Silver, model no. MD789LL/A, or Space Gray, model no. MD786LL/A, for $509 with free shipping. That's $11 under buying a new unit. A 1-year Apple warranty applies for all refurbs.
A 90-day warranty is applied, although its unclear who backs it.
Update: The Apple Store also offers the 2nd-generation factory-refurbished Apple iPad mini 8" 32GB WiFi Tablet with Retina Display in Space Gray or Silver for $419 with free shipping.
Note that this used item may be be missing parts or accessories and may show signs of wear. No warranty information is provided.
Also available is the the 2nd-generation Apple iPad mini 8" 16GB WiFi Tablet with Retina Display in Silver, model no. ME279LL/A, with a $50 Target Gift Card, for $399. Opt for in-store pickup to dodge the $6.13 shipping fee. (Note that availability for pickup is limited by ZIP code.) Assuming you'll spend the gift card, that's $50 under the lowest shipped price we could find elsewhere. It's 7.5mm thick, weighs 0.73 lbs., and features an Apple A7 64-bit processor, 7.9" 2048x1536 LED-backlit IPS display, FaceTime HD front-side camera, 5-megapixel iSight camera, 802.11n wireless with MIMO, Lightning connector, and 10-hour battery life.