Best Buy offers the Samsung SmartThings ADT Smart Smoke Alarm for $19.99. Choose in-store pickup to avoid the $5.49 shipping charge. That's the lowest price we could find by $17. It allows you to set lights and other connected devices to turn on and off automatically when carbon monoxide is detected.

Also available is the Samsung SmartThings ADT Home Safety Expansion Kit for $39.99 with free shipping. That's the lowest price we could find by $25. It includes a carbon monoxide alarm, smoke alarm, and water leak detector.