An interesting story that I'd like to relate, is that of a 13 year old boy employed by my aquarium supplier to looks after tanks etc; who recently decided to breed discus.
The owner (and myself) were dubious at best, lamenting that he would buy two great quality adults to either end up with them dying, or the fry quickly dying off if he got that far. Even worse, was when I seen the 2.5 foot tank (30 gallons perhaps maximum), set up with two small sponges and overrun by algae. I was worried the impending disaster would ruin his enthusiasm for the hobby.
Fast forward a good few months, and he has a good few batches of fry growing in separate tanks; having just sold the entire first batch for a value close to £300 (455 dollars). You tell me that isn't a lot of money lol.
Given that I expect his other batches will sell well (he can also post), I wouldn't be surprised at regular takings of at least 210 dollars (to you guys) every month or so, which is more than enough to cover his costs.