Bettas are great fish for all types of people, even non-fish people. They can be kept in a betta hex, which is about a quart of water, or a 10 gallon tank. The more room, the happier the fish will be. Remember males must be kept separate from other males (always) and females (except when breeding)!!!
Determining the size of the quarters is determined by, budget, time available, space, and interest. You would be surprised to find out that a fish living in small quarters, will need more care that one in a 10 gallon. A water changing schedule can go as follows:
One quart or less, everyday to everyother day
1/2 gallon and less, every third day
one gallon, once a week
2-5 gallons, partial water change
5+ gallons, partial water change once everyother week.
Pretreat your tap water with a declorinator, such as Amequel, or Right Start. These will get rid of the chemicals which are too harsh and add in stuff to keep your betta happy. Always use room temperature, around 74-80 degree, water, not too warm or too cold (you don't want a fishcicle!). By keeping a gallon jug of water pretreated in a old milk container, you will never have to worry. I have gallon jugs just about everywhere in my fish room!
Bettas are jumpers, so keep your tank or bowl covered to prevent a kamakazee fish.
Feed twice a day using floating pellet food, about 2-3 pellets and you will see how excited your betta becomes when you approach. They are smart little fellas.