Amazon offers the 2nd-generation Nest Learning Thermostat, model no. T200577, for $199 with free shipping. (Abt and Home Depot also have it for the same price, while Best Buy offers it for a buck more.) That's $29 under our June mention and the best price we've seen. (It's a current low by $50.) The 2nd-gen improves on its predecessor with a slimmer profile and 1-piece construction. It "learns" how you set your home's temperature, downloads data and can be controlled from your smartphone (via built-in WiFi). Note that not all home HVACs are Nest-compatible; click here and click the "compatibility checker" to see if it will work with yours.