Emerson Thermostats via Rakuten offers the Emerson Sensi Smart WiFi Digital Thermostat for $129. Coupon code "HOME20" cuts that to $103.20. With free shipping, that's the lowest price we could find by $5, although it was $24 less in December. This thermostat is compatible with Amazon Alexa, Apple HomeKit (c-wire required), Wink, and Google Assistant. It allows for WiFi control via Emerson's iOS or Android app. Two AA batteries are included.