If this is supposed to be an attempt at evening out the costs of the hobby, neither species will earn you enough to break even. I won't even talk of any profit, because unless you breed rare species and have a great network of specialists and wholesalers there is no profit to be made with fish unless you make it your main business.
Oh, definitely the danios..
Try and find some nice long fin versions.
They are super easy to breed and collect eggs from, also the young are not aggressive towards each other so you can keep more than one batch together...
I breed mine this time of year (spring just started but it is still too cold outside overnight), but soon the fish larvae will be free swimming and ready to go out to some flow bins with water I have set up outside as ponds... they will be ready to resell by the time it gets cooler again next year.
I've done the neon ones before as well as the crosses with normal ones...
I noticed you also get a super blue stripe version now... quite pretty, but I still love the long fin version standard zebra or leopards the best. They are really good at calming down skittish fish because they are dumb as wood and rarely dart around or act stressed and always make the food look extra good with their eagerness.