B&H Photo Video offers the Swann Home & Business Alert Alarm for $17.99 with free shipping. That's $2 under our mention from a month ago and the lowest price we've seen. (It's the best price we could find now by $19.) Deal ends December 27.

This kit includes a doorbell, two weatherproof motion sensors, and indoor chime speaker unit. It features a wireless range up to 200 feet, motion detection up to 20 feet, and 16 different chimes with three volume levels.