Disclaimer: I've only had bettas for a few months now. That said, here's another potential option:
I have 3 gallon acrylic critter keepers for each of my three fish. They cost $13-16 at Petsmart, Petco or Amazon. (There is also an extra large, which holds about 5 gallons and costs a few dollars more.)
Pluses: I do frequent water changes, and these are easy for me to lift. I can easily dump the water, wash the tank and refill it. (A similar sized glass tank is heavier.) I also like that there's a lot of horizontal swim space for my guys.
Negatives: They scratch easily. (And I've heard they can break, but I haven't had that happen.)
I have heaters in each, and the water temp is maintained at 79F.
I don't have filters, but I do one 100% and one 50% water change per week.
Also, there's no light, which might be an issue if you want to have live plants. (During the warmer weather, I had a Pothos growing out of the lid. So the amount of light would also depend on the plant.)
If you check these out at Petco, they're ususally in the fish aisle. If you go to Petsmart, they're usually in the reptile aisle.
Here's a link to the Petsmart one, so you can see what I'm talking about