Nest threw out all of the old assumptions about home security systems, and built something pretty great with the new Nest Secure, and you can save $100 on the usual price of the starter bundle today on eBay.
$400 gets you the Nest Guard (the big keypad thing that doubles as a motion detector), a couple of Nest Tags that can disarm it instantly, and two Nest Detects which can monitor entire rooms for motion, and also detect when windows or doors open.
Gizmodo’s review has more details about how all of these pieces fit together, and there are more add-ons that you can purchase a la carte to fit your home’s needs.