Newegg offers the refurbished 2.4-lb. Apple MacBook Air Intel Haswell Core i5 1.3GHz 11.6" Laptop, model no. MD711LL/A, for $444.99 with free shipping. That's $2 under our mention from July and the best price we've seen for it in any condition. (It's also $5 less than the lowest total price we could find for a refurb today.) It features an Intel Haswell Core i5-4250U 1.3GHz dual-core processor, 11.6" 1366x768 LED-backlit display, 4GB RAM, 128GB SSD, 802.11n wireless, Bluetooth 4.0, Thunderbolt, USB 3.0, and Mac OS X 10.9 Mavericks.
A 90-day warranty applies, but it's unclear who backs it.