What I would suggest is buy an ootheca that you can release, release about half and then raise the rest for feeders. Possibly sell off the half instead of release, if your looking at a hundred praying mantids they each are a pet themselves let alone feeders. Bet you can find buyers for baby mantids from other local chameleon owners.
Also, put a ad in the local gardening clubs as they are a non-toxic form of pesticide (they eat everything like chameleons do) thats why making sure they are releasable in your state is important.
They could possibly pay for themselves, chinese mantids can likely range 1-2 dollars per mantid depending on the buyer and molting. If you have something more exotic that you can't release you can sell them off as pets or feeders, I've seen mantids go for 35+ as pets. Thats the mantis itself, not its ootheca. (Orchid Mantis)
Mantids were my first love, I do plan on finding a suitable mantid to breed and feed off as treats after I get dubias and horns set up.