another problem with using egg crate would be the fact that if you do feed live crickets, they will surely get out. Me and my buddy had probably about 20 lizards/frogs in our last place and they can get out of almost any enclosure, they love to chew holes in soft plastic, I also don't know if petsmart feeds their crickets, because your frogs can only be as healthy as what the crickets are eating, so "gut loading" is usually suggested.
I gut loaded my crickets for my chameleons, they sell little cricket cases that have tubs in them, you can get a couple dozen at a time and keep them in there with some cricket meal and your frogs will be happy as .....well frogs
Just my personal experience
Josh