This Nest Learning Thermostat (Third Generation) drops from $249 to $199 at HomeDepot.com. Plus, shipping is free. This is the lowest price we've ever seen for a third-generation Nest thermostat (although once we saw it for $200 with a $30 gift card). Better yet, click on "get rebates" underneath the price and enter your zip code to see if you're eligible for $10-$100 in rebates from your local energy company (it worked with dozens of the zip codes we tried!) It's wifi enabled, includes batteries, and is highly reviewed. Sales tax is charged in most states.