Expercom offers the refurbished Apple iMac Intel Core i3 3.06GHz 21.5" Desktop, model no. MC508LL/A, for $646.52 plus $21 for shipping. That's tied with last week's mention and $170 under the lowest total price we could find for a used unit elsewhere. This iMac features an Intel Core i3-540 3.06GHz dual-core processor, 21.5" 1920x1080 widescreen LCD, 8GB RAM, 500GB hard drive, SuperDrive, ATI Radeon HD 4670 256MB video card, Bluetooth 2.1+EDR, AirPort Extreme, iSight, Apple Magic Mouse, Apple Wireless Aluminum Keyboard, and Mac OS X 10.9 Mavericks. Deal ends October 13.

A 90-day Expercom warranty applies.