I housed mine in beanie baby display boxes. They're tall and easy to clean and lightweight. (And not glass!)
Breeding was done in 10 g tanks, filled about 1/3 full. Once the male had eggs to care for, the female went back into her 'jar' and he cared for the eggs until the babies hatched and were free swimming(or attempting to free swim, dad will keep spitting them back into the nest). Once dad is out, the water can be raised to 2/3 full or even full, and the babies are fed on any of several various diets.
Diets can be trout chow(available from feed stores) and babies sometimes can be fed the same food, ground up in a blender. The very tiny babies do better on things like vinegar eels or the teeny nemotodes you raise in oatmeal. I can't think of the name right now. Brain no worky yet, havin't had tea yet this morning.
Some people told me to expect several failed tries before having any success, and that certain colors were known to fight instead of breed, that many issues would arise and frustrate me in my efforts to breed bettas. Instead I ended having bred the hardest(reds) the first time and ended up with over a hundred 1 inch babies in the first try.
Of course, I had spent the last 4-5 years breeding seahorses. I was a ringer, you could say.
All in all, it can be way fun to do. I'd suggest bypassing the pet store fish altogether though. Go ahead and get quality bettas and get a few pairs to begin with, in case someone decided to fight instead of breed, you'll still have another pair to try with.
Feed quality food, and breed your own foods when possible.