MegaMacs offers the refurbished Apple iMac 21.5" Intel Core i3 3.06GHz Desktop PC, model no. MC509LL/A, for $579.99 with free shipping. That's $219 under our February mention of a used unit and the lowest total price we've seen for a 22" iMac with a Core i3 CPU. (It's currently a low for a refurb by $174.) Features include an Intel Core i3-540 3.06GHz dual-core processor, 21.5" 1920x1200 LED-backlit LCD, 4GB RAM, 500GB hard drive, dual-layer DVD burner, 802.11n wireless, Bluetooth, iSight webcam, and Mac OS X 10.10. Deal ends April 22.

A 30-day MegaMacs warranty applies.