Best Buy via eBay offers the second-generation Ecobee Ecobee3 Wireless Thermostat with Remote Sensor for $185.99. Apply coupon code "P20MEMDAY" and checkout with PayPal to cut it to $148.79. With free shipping, that's the lowest price we could find by $46 and within a buck of the best deal we've ever seen. (We saw it for $1 less six days ago.) It includes one remote sensor (with support for up to 32), which can track temperatures across your home for more accurate temperature settings. It also features a color touchscreen, timer, and remote control smartphone app. Deal ends May 29.

Note: This coupon can only be used once per PayPal account within a single transaction.