When I was in high school I had an Edmund Scientific kit that came with a baggie of uranium ore powder and some radium paint for particle sources. Sadly, they don’t sell that any more.
When I was in middle school I believe I bought a pretty extensive chemistry set secondhand. Various small bottles of poisonous chemicals, test strips, and all sorts of glass. Sadly I see nothing comparable out there today. I think the strongest chemical in today's kits might be vinegar.
The website that links to this file doesn't contain much else but here it is anyways because the manual went through several revisions (and might get updated in the future?).
You can use peltier heat pumps to make a chamber cool for a cloud chamber.
I tried using a plastic tub on top of the peltiers, but I think that was a bad idea, as the tub probably acted as an insulator as I didn't get the tub cold enough iirc (or maybe the plastic was just too thick too).
(Although the peltiers themselves had ice around them)
Anecdotally, I never had any success with this. I bought several cheap but powerful (100W-300W) 12VDC Peltier elements off Amazon. With the hot side bonded onto either a massive chunk of aluminium or a CPU cooler, the cold side never reached less than minus a few degrees C. Open air mounted or with some cling foil insulating it from air (ambient was probably around 25-30C). I also tried stacking a second (up to 50W) Peltier on top of the first, but that was even less successful. Just to say that it's not quite that trivial to get to -20C using Peltiers. If anyone likes to share their more successful experience, I'm all ears!
I really like a cloud chamber that I can put together in the pub whilst potentially drunk. A pint glass and some dry ice does the job (dry ice being obtainable from a fire extinguisher - not that I'd recommend you grab one off the pub wall without replacing it refilled).
