AltaTac via Walmart offers the D-Link 802.11n Wireless Day/Night Surveillance Camera in Black, model no. DCS-934L, for $39.95 with free shipping. (Jet.com has it for the same price with free shipping.) That's tied with our mention from September and the lowest total price we could find by $7, outside of the mentions below. It features integrated motion-sensing technology, up to 16 feet of night vision, and a mounting kit.
A couple of close prices: Amazon has it for $40.77 with free shipping for Prime members, and Groupon has it for $40.99 with free shipping.