Fully adult dubia roaches might be too big for the frog, but juvenile roaches should work. I have a small colony in a tupperware container with mesh on top. (And a locking lid! That's important.) It doesn't smell like crickets do, roaches don't die as fast as crickets, the roaches can't climb and once the colony gets going you should have plenty of tiny roaches.

Cons: You'd have to convince your mom to keep roaches. Roaches are still fast. It might take a while for them to start breeding.