Tupperware for sportsmen
Every time I leave a local gun show I try to carry out at least one 50 cal. ammo can. I can usually get one with a good seal (rubber o-ring) for about five dollars. I store primers, pound cans of powder, and many rounds of reloaded ammunition in these cool Tupperware for sportsmen type containers. For a little more money you can buy really cool big ones that will hold a keg of powder. I only have a couple of those because I can never come to grips on any one powder.
Support your local gun shows. That's where all the cool people hang out.