Just gonna give you my personal experience and opinion here and hope it doesn't offend you. Making money on fish is hard thing to do in my experience. Unless you have a LFS that's willing to buy offspring on a regular basis as well as a large tank or many smaller ones to house multiple pairs, you'll find that your cost will pretty much eat any profit you could hope to make. Meaning you probably won't make any money on them just match the cost. Between feeding the fry and the regular tank maintenance you'll struggle to make any money. That's why there's barely any small breeders that specialize in certain fish. The exceptions are probably ray breeders, discus, rare angels and certain african cichlids. Even then it requires fairly large set-ups including multiple tanks to make a profit and these can be some high profit fish in regards to cost. I've tried it myself with more tanks dedicated to breeding and had some pretty rare cichlids and still couldn't find a reliable customer base and found myself sitting on fry for months eating away at any profit I hoped to make on them. Still if you have to try I'd say your best bet is the electric blue rams which can fetch a pretty penny in regards to how much you can get for fry in comparison to how much cost would be involved. However you stated you money resource is limited so you probably can't afford a breeding colony right now. Still in my opinion it would be best for you to save to try and get a colony of these guys as they're the only cichlid I could see you breeding in a 40 bow front and hoping to make a profit on. Again it's not my intention to offend you, just trying to help by being as informative and realistic as possible with you. I wish you good luck and if you succeed(which I hope you do) I'd love to see a thread on here detailing your success and breeding stock.