Woot offers the factory-refurbished HP Pavilion 19-2114 AMD 1.4GHz 19.5" All-in-One Desktop PC for $299.99 plus $5 for shipping. That's $45 under the lowest total price we could find for a new one. It features an AMD E1-2500 1.4GHz dual-core processor, 19.5" 1600x900 LED-backlit LCD, 4GB RAM, 500GB 7200 rpm hard drive, AMD Radeon HD 8240 graphics, DVD burner, 802.11n wireless, media card reader, USB 3.0, and Windows 8.1 64-bit. A 90-day HP warranty applies. Deal ends September 18 at 1 am ET.
Update: Specs corrected.