First, you need to do a lot of research on the subject before you think about it. Another thing is that bowls that can't be heated and filtered are inappropriate housing for bettas. IMO, optimum tank sizes for a sole betta are 2.5-10g tanks *with* heaters and filters.
I, like the others, urge you do reconcider breeding bettas. It takes a lot of time and patiences and there is more too breeding them than just sticking the male and female together... it can sometimes take up to a month for both fish to be ready to breed. Then, it takes another two months to get the fry to a sellable size and you'll need 100+ jars to seperate the males into... in those jars you'll need to do daily water changes. On top of all this, you'll have to find someplace to take them. You probably will not be able to sell them, just give them away. Fish stores get bettas dirt cheep and will only be willing to buy them from you, at most, what it costs them to get them from the suppliers... so you'll be looking at *maybe* 40 cents each... So, suppose you get 50 fry to a sellable size you'll maybe get $20 (credit not cash) at the store. But, then you have to subtract food costs, housing costs, electrical costs, and you're time.. by the time you're all said and done... you'll be lucky if you make any profit at all or at least don't lose any money.
So, unless you have hours a day to spend with these fish and the money to properly house 50 or more fry (assume 25 males = 25 seperate 1quart jars that need cleaning every day) and the time to spend on a good amount of research; breeding and raising these wonderful fish properly isn't feesable.