My wife came home with some Sugar Free Juicy Fruit Gum containers that I have saved for the same purpose as you. Rivet storage containers. The top has two flip lids, a big one to add rivets and a small one that should be about right to dispense rivets.
http://www.amazon.com/Wrigley-Juicy-.../dp/B0055IWHKI
I haven't compared the price nor how well they work, but hey, she bought them and was going to throw them away, so to me they are free!