I use various containers as i cast so I'm always looking for something to use. Old coffee cans of various sizes, thick plastic containers like these are great for bulk pistol bullets.

For small amounts(think 100ct boxes of 7mm or 22 cal bullets) I use small containers I have sitting around. I have like 12 of these that I use for old 100ct boxes that I get at estate sales that are falling apart.

I also use those plastic soup containers you get with Chinese takeout. They work great and are fairly strong(although I wouldn't put much side to side pressure on them).