Tanga offers the refurbished Apple iMac Core 2 Duo 3.06GHz 27" Desktop for $599.99 with free shipping. That's the lowest price we could find by $19. It features an Intel Core 2 Duo 3.06GHz processor, 27" 2560x1400 LCD, 16GB RAM, 1TB 7200 rpm hard drive, ATI Radeon HD 4670 256MB video card, SuperDrive, AirPort Extreme, iSight, and Mac OS X 10.12 Sierra.

A 30-day warranty applies, but it's not clear who backs it.