We negotiate a price, and I buy your male Betta fish. If wanted, you may have up to a quarter of the fry after about 4 - 8 weeks, when they are at least partially colored up, so you may have your pick of the batch. I may say no to certain ones if I have a liking to them, but it will only be maybe 2 or 3 I keep and sell the rest.
Option two:
You lend me your male for temporary breeding. Proper conditioning and the actual spawning process will take anywhere from a week to a month, and the male will need to tend to his bubble nest for 3 - 4 days. Be warned that the breeding process can be pretty tough on males, he may get a few fin nips but don't worry, with proper care these will heal. After about 4 - 8 week, when they have partially colored up, you may have up to half of the fry.