I have used the empty little cups the Meal Worms come in, Empty coolwhip container, disposable tuppaware, etc. Just use something with smooth edges that the feeders cant crawl out of that easy. With Crickets I always have a few Jumpers that get out but usually isnt a problem.
I use deli cups. Tall ones for larger chams and short ones for the small guys. One thing that you have to do with cup feeding is clean the cups out on a daily basis. Anything on the bottom of the cup you are using gets ingested by the chameleon. Mine seem to aim at them when they poop for some reason. Its also a good idea to add holes in the bottom for drainage.
A good feeder cup can be made with a small tupperware container. Cut most of the bottom away and replace it with screen, use hot glue to secure it. That way bug waste and water won't accumulate during misting and your bugs don't drown.