Sorry no body replied, I hope it's not too late.
Deli cups with craft screen works great:
Deli cups:
http://lllreptile.com/store/catalog/reptile-supplies/deli-containers-shipping-boxes-packing-material/
You can probably talk your local Deli into selling or giving you some deli cups. Use a drill or a very sharp knife to make holes as seen in the link.
Craft Screen aka Plastic Craft Mesh or Plastic Canvas is great, especially for raising silkworms and hornworms
Find it in the WalMart craft/fabric section, or at any craft or fabric store. I know JoAnn's carries it, Michael's should as well.
It's usually used for latch hook, in case you have a hard time locating it in the store.