Home Depot offers the third-generation Nest Learning Thermostat in Black, model no. T3007ES, or White, model no. T3017US, for $199. Add it to your cart and the price drops to $149. With free shipping, that's $20 under yesterday's mention and the best outright price we've seen. (It's a low now by $50.) Improving on its predecessor with a slimmer profile and bigger display, this thermostat "learns" how you set your home's temperature, downloads data, and can be controlled from your smartphone via WiFi. Note that not all home HVACs are Nest-compatible. Deal ends December 1.