Groupon offers the Defender BlueLine 16-Channel Security DVR with 16 600TVL Cameras, model no. 2117, for $479.99 with free shipping. That's tied with our August mention as the lowest total price we've seen. (It's a current price low by $120.) It features 16 weather-resistant 600 TVL cameras, night vision range of up to 75 feet, 500GB hard drive, USB, Ethernet, and remote viewing. Deal ends September 26.