PK: Foamcore is available at almost any craft store. I happened to buy mine at Office Depot in the "presentations" section (where the easels and projectors are). I bought 3 huge sheets (30" X 40" I think) of it in a pack for about $13.00. I probably used about $1.00 worth of it for the pouches.
I probably used $2.50 worth of my vinyl making the pouches. I could have bought cheaper vinyl than $5.00/yard, but I liked the way this vinyl looked.
I'd say I did all 8 pouches, minus the belt, for under, or right at, $5.00.
Jedi-Bob: Thanks for the compliment! The guys at Radio Shack know me by name! (I'm NOT a geek! well, ok... MAYBE I am... a LITTLE)...
I never considered using project boxes. They're more durable than foamcore, but hopefully mine won't have to endure anything too drastic. 