Why save 100 $ on an unwarranted thermostat, or one you could ruin or
have not work by improper install.

Carrier- Bryant, Lennox, and others have thermostats that have outside
sensors, fan run speed, humidifier controls, Low Speed humidity removal
modes in AC " which with VS DC pull double the moisture out, good on 72f
days", etc etc, more than you want to hook up or know how to do right.
Put the wrong wire on or with power on and things can fry.