I have been asking about this locally, here in Oregon, and it seems that in the US we're likely to get some financial incentives. But nothing seems sure yet. Anyone here happen to know anything?
Some of the incentives may be limited if you have too much income.
I was able to get the latest Ecobee thermostat for $90 instead of the list price of $250.
Fortunately or unfortunately, I started reading about how 3rd party thermostats can't talk to multi-stage furnaces or air handlers except in very blunt increments. Maybe as blunt as on or off. Each manufacturer has their own, undocumented protocol for doing fine adjustments. I tried running the fan all the time (now I do 10 minutes every hour) and it was quite expensive for that month. Anyway, I'm hesitating about putting in the nice Ecobee thermostat because it could conceivably cost quite a bit more in electricity.