Aksauctions via eBay offers the refurbished Apple MacBook Air Intel Haswell Core i5 1.4GHz 13.3" LED-Backlit Laptop, model no. MD760LL/A, for $579.99 with free shipping. That's $50 under our July mention and the lowest total price we could find now by $20. (It's also the best price we've seen for this model.) It features an Intel Core i5 1.4GHz dual-core processor, 13.3" 1440x900 LED-backlit LCD, 4GB RAM, 128GB SSD, 802.11ac wireless, Bluetooth 4.0, Facetime camera, Thunderbolt, and Mac OS X 10.9 Mavericks.
Of note, no warranty information is provided.