It all depends on what you work out with your lfs. These little corys aren't expensive to buy and their fry won't sell for a high price. Breeding them will give you the experience you need to later raise more difficult and therefore higher priced ones.
I like to work out a deal with my lfs where I trade my fry for a certain amount of store credit. I spend a lot of money with him anyway and this gives him a little more flexibility, so I get a higher price for them.
Talk to the store owner ahead of time to see just what he will offer and how big the fry should be. It will vary from one store to another. Perhaps you will have to start out at a lower price the first time, but after he sees that you are a reliable provider of healthy fish, you might be able to get a better deal.