Back in the day, I use to have MTM or RCBS plastic cases for all my ammo. But then I only loaded maybe 100 rounds a quarter or so.
As my shooting became more prolific and my reloading more voluminous I ditched the plastic cases for zip lock bags. All except for the rifle rounds which I still put in plastic cases.
Then I moved in to shooing revolvers with moon clips. A whole 'nother game, storage-wise. You can't just throw them in a bag or box and let the rattle around. You have to be careful the clips don't get damaged. I remember seeing a shooter at a match who used coffee cans (3# size), but those seem a little large for me. I wanted something that held about 100 rounds, in the clips.
Also back in the day I use to provide pyrotechnics for some indoor theatre. That ended after the RI-Great White Fire. Not that I felt I was unsafe, but venues either prohibited fireworks or put so many restrictions that it effectively locked me out of the side business. But I had several cans that the small fireworks (gerbs) came in. PERFECT FIT. I could get 3 layers of 5 each .45ACP clips (90 rounds) or two layers of 8 round clips with .357Mag (80 rounds). I've used them for a couple of months and they work wonders.
Here's a picture and as you can see the pyro labels are still on the cans, which is humorous, at least to me.

Now where to find more. They are, almost exactly 4" in dia and 4" high (without the top). I finally found a dealer today and spent a grand total of $30 to get 10 more cans.
http://www.e-cookietins.com/tins-cans/upright-round-cans/quart.html (Don't laugh, yes e-cookietins)
Just thought yall like to know.