(Semi) newbie here with many, MANY questions!

[Mr. Misha]

But it seems like all the ones with the probe(s) that I look at are either way above my price range (which is $20-$30 or so) or are riddled with middling to negative reviews about how they work only for a month or are inaccurate from the get-go.

I have one of these that have decent reviews that are within your budget and they come with a probe. They're also made by Vivarium Electronics that make proportional thermostats that have been a good industry standard. I'm sure you can do some googling regarding people's opinions:
https://www.reptilebasics.com/thermometers/TH-100/