Can anyone direct me to where I can purchase plastic business card cases big enough to hold packet tricks? I have plenty of business card sized folders, but very few of the larger ones, and I need more.

This sounds like a Staples thing. It's an office store that always has awesome supplies for magic even if they don't realize it.

Look at their Vault boxes. They hold 8 decks of cards so well it seems unlikely they're meant for index cards. They have heat activated ink markers. They have both wet and dry erase markers. The list goes on.

Other than my decks, about half of my kit comes from Staples and Dollarama lol.

Http://www.penguinmagic.com/p/447