eCOST offers the refurbished 2.9-lb. ASUS Zenbook Intel Core i5 1.6GHz 13.3" LED-Backlit Ultrabook, model no. UX31-RSL8, for $569.99 with free shipping. That's $50 under our November mention of a refurb and the lowest total price we've seen for a 13" ultrabook with a Core i5 CPU and 128GB SSD. (It's currently $30 less than the best we could find for a refurb elsewhere.) This ultra-slim laptop is 0.7" thin and features an Intel Core i5-2467M 1.6GHz dual-core Sandy Bridge processor, 13.3" 1366x768 LED-backlit widescreen LCD, 4GB RAM, 128GB SSD, 802.11n wireless, Bluetooth 4.0, webcam, one USB 3.0 port, 50-whrs polymer battery, and Windows 7 Home Premium 64-bit. Note that no optical drive is included.

A 90-day warranty applies, although it's unclear who supports it. Note that eCOST lists the resolution as 1366x768 while other sources list it as 1600x900. ASUS doesn't mention which resolution this model uses.