Verizonwireless has the nest thermostat for $249.99 with a $50 visa gift card. Combine with amex offer to get another $25 off (i.e., 10%). 2 day shipping is free and tax likely applies
Check your local energy companies to see if there are any further discounts / rebates (Coned in NYC has a $25 rebate)
https://www.verizonwire