Try thrift stores / Craigslist / Kijiji / garage sales (after COVID anyway) and of course secondhand building supply stores like (here in Canada) Habitat for Hu

Try thrift stores / Craigslist / Kijiji / garage sales (after COVID anyway) and of course secondhand building supply stores like (here in Canada) Habitat for Humanity Re-stores. Those things are everywhere. Bonus points for finding a round Honeywell. Another trick that works (I used that to get a replacement panel for a no longer made garage door) is just call up the outfits that install them and offer them a reasonable sum for a "pull".