have you done all your research first?
A lot of people underestimate what is involved when breeding bettas. As OG said, as the male fry age, they will each need a separate tank/container. That can mean 150 individual quart containers that need to be water changed and fed and maintained temperature wise.
Also, a lot of the time, there is no demand for bettas because of their availability at a pet store for very little money. Many people who raise bettas cannot get rid of them all and end up with bettas they originally didn't intend to keep.
You might find that you would need to sell them online. In which case you'd need to package them properly for shipping and whatnot.
If you were very serious about this, you would invest in a pair of true breeding worthy fish, say from topbettas.com, and that way they wouldn't be "plain" veil tails that are available everywhere you turn.
If you do your research and are still interested, I could get you in contact with someone I know that raises bettas to sell.
EDIT: There is also always the risk of having your female or even male killed in an attempted breeding session. Unless you know how to read the signs of the fish, what seems like a harmless love bite may turn deadly. It happens quite a bit.