Lots of bugs last a long time, so its okay to buy a larger quantity and use them slowly. Dubia Roaches for example last without much effort - just a bucket with some holes punched in the lid, an empty egg carton, a little food (gutload well in the days before feeding any to your cham). Keep the bucket in a closet and no one will know they are there.
Silkworms you can buy as eggs that you keep in the fridge - just take out and grow up a months worth at a time.
Butterworms you can keep cool and they will last dormant for a couple months, then just warm up and gutload those that youre going to offer to the chameleon in the coming days.
Superworms will also last a long time with minimal effort.
you might also approach your local pet store, ione that sells reptiles, suggest they try selling butterworms or whatever. They can buy in bulk and then sell in small numbers too all lizard keepers, at a profit. You'd pay more, but it would be convenient.