Breeding silkworms is a bit more trouble than it's worth, especially when egg prices are so low. You'll find keeping a healthy stock with silkworms can be a difficult enough task in itself without having to worry about breeding, not to mention keeping the proper schedule of mating, laying, hatching, and raising phases which can get complicated quickly if you're trying to stay consistent with it.
My suggestion is to look up "Sericulture" on google, as this is the art of raising silkworms. Learn all you can about what you're getting into, do it as a hobby first, then if you have an excess, sell off that excess. Concentrating on the money aspect can really rob yourself of enjoying a truly beautiful art.