Amazon offers the Emerson Sensi Smart WiFi Digital Thermostat for $97.99 with free shipping. That's the lowest price we could find by $30. 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.

Update: The price has dropped to $94.63.