In fairness to all, we don't discuss pricing on the Wall. Thanks for your cooperation.
For heating, we always connect wires to RH and W to call for heat. Until now, I never realized that if you connect a neutral wire from the transformer to terminal C on the thermostat, it will power the thermostat and you don't need to change the batteries.
Most of you will say "Duh", but I just never knew that.
Often wrong, never in doubt.