Altatac via Rakuten offers the Nest Secure Alarm System Starter Pack for $399. Coupon code "SAVE15" knocks that to $349. With free shipping that's the lowest price we could find by $50 and the best outright price we've seen. (Other major retailers charge at least $499.) It includes a Nest Secure Guard, two Nest Tags, two Nest Detect Motion Sensors, and mounting hardware.