Sinsarity. Its not that much fun. You will likely be faced with having to kill some off (feeder fish, defects, etc) and a lot of natural deaths.
Bettas can produce 400 offspring in a single mating. Also, it will take 6-8 months of cleaning 80 to 150 jars every week before you can sell them or give them up to stores.
Anyhow, it that does not discourage you, and you can face the reality of having to put them all to death if they end-up with deformities, then do a lot of research, save your money (about $300 in tanks and supplies), and go to it!
FYI, I am going to breed my first set of bettas in 3 weeks. I have been researching it for 4 months, visited a local breeder, and been conditioning 2 pairs for the past month.
To answer your direct question, I am going to sell them mostly, and I started a list of pre-orders already. Some I may be able to trade for store credit at some of my LFS, but mostly I plan on selling as much as I can directly to people.
Remember, plan ahead!