ExperCom offers the refurbished 5-lb. Apple MacBook Intel Core 2 Duo 2.4GHz 13.3" Widescreen Notebook in Black, model no. MB404LL/A, for $549 plus $13.50 for shipping. That's the lowest total price we've seen for this laptop with 4GB RAM. (For further comparison, we saw it in white with half the RAM and a 125GB hard drive for $114 less in May.) It features an Intel Core 2 Duo T8300 2.4GHz dual-core processor, 1280x800 13.3" display, 4GB RAM, 250GB hard drive, iSight webcam, Airport Extreme 802.11n, Bluetooth, Mac OS X 10.6 Snow Leopard, and more.

A 90-day warranty applies, but it's unclear who backs it.