I got mine online. It heats my 20 up nicely
I need to get more!!! lol. Free shipping, world wide, between 6 and 30 dollars usually depending on size.
Bettas come from Thailand, aka a tropical place... But because stores sell small containers since they can breathe due to the labrynth organ, they are kept in tanks that heaters are dangerous to use in... Now they make bowl heaters, but those are iffy and are preset.
For breeding, 82-84 degrees seems to be the norm, and immitating the natural habitat with "rain" (I use a spray bottle), lowering the water, adding cooler water, tannins, etc, usually helps. Plus conditioning - fill them up with frozen, freeze dried, pellet and live foods. Mine are getting mealworm meat, which the mealworms were being gut stuffed. Never toss two together, because they have to be ready :) Make sure the gal is eggy too - usually helps.
Do a bit more research, of course! You'll never be able to learn everything by reading, but you can learn a lot and get the appropriate fry foods, jars, tannins, meds, etc