I'm gonna disagree with some of the above statements, but agree with the overall sentiment.
What I disagree with is the idea that you have to spend hundreds of dollars on the initial breeding stock. If you want to breed show bettas, then of course you'll have to start with show bettas (or create your own line, which would take an amount of effort many times greater than just breeding a pair of bettas). However, if you just want to breed some bettas, all you need is a pair of juveniles (though finding juvies at stores can be kind of tricky). Think of bettas like you'd think of dogs. The known lines of show bettas are like purebreed dogs, while the typical storebought ones are like mutts. Purebreeds sell for much more, but that doesn't mean that the mutts can't breed. In fact, in many cases, the mutts breed much better, because they don't have much (if any) inbreeding tainting the line.
The same thing can be seen in koi lines. The show ones don't breed quite as well, periodically forcing breeders to "sully" their lines with junk koi. There was a point in koi's history that wild carp needed to be reintroduced to strengthen the koi's genetic base. The fish had grown so week from inbreeding that the species would have died otherwise.
Either way, it's best to have buyers for at least dozens of bettas lined up before you begin breeding. This is easier with purebreeds, since people are more likely to want to pay good money for, say, a black halfmoon than for a mutt veiltail (though I'd likely go for the veiltail, the amount I'd be willing to pay wouldn't help absorb the costs you've incurred in the breeding).
As far as I know, bettas would make okay feeders for larger fish (as long as the person using them as feeders can get over the whole idea of the bettas being cute), but again, selling them as feeders isn't going to recoup much of your costs.
I am going to agree that it is extremely expensive and time-consuming.
Whether you buy show-quality purebreeds or mutts, you'll need a good mix of high-protein, high-quality food to condition the pair to breed (this will also take a good chunk of time).
You'll need time to devote to the breeding itself, because it's best to monitor the process. Sometimes they don't quite get the process of breeding right and can really hurt each other without actually accomplishing anything.
Because there's no humane way to only raise three fry, you'll need a whole bunch of shelving filled with jars (for once the fry are old enough to get belligerent with each other) and several hours available each day to feed them and change their water.
You'll need shipping supplies (unless all of your buyers are local) and a few extra tanks to keep adults who end up not getting sold.
So, even if you're starting with a pair of "junk" juvies (these could even be a pair of undesirables from a show-bred line), your cost in both time and supplies is going to be astronomical.
If you want to toy around with breeding, it's usually better to start with something easier to breed, like guppies, and get used to the very basic ideas of dealing with fry, then work your way up from there. That's what I'm doing.
Similar Aquarium Fish Forum Threads 
