Search Amazon for TUYA thermostat. I found options for as low as $25. If you want something that’s actually going to be a good product, the Amazon thermostat is good I guess, it just is insanely walled off from everything else. Something that is worth considering as an alternative is the Wyze thermostat.

Ecobee has been fantastic for me. It’s easy to use and got a rebate through our electric company(check your power companies website). Highly recommend.

I have just started with a system mainly because i had to. the olf system would not function after April 2024 and i really liked having the control of the heating system when away or coming back early etc.

I got an offer on the Schneider Wiser system. you do need the heating controller too though. worth a look if you can get it in your country but it does depend on your budget of course.