I don't know of any places to get them at retail. Try some online collecting gear websites. The star cases are okay, but as mentioned, pretty big, but they do the job. I've got a couple of Joes in them myself.
Are you going to put them in cases and store or display? That'll help make the decision a bit. If you're storing, get the Joe-specific ones as you'll store more in less space. If just displaying, the star cases would be just fine so get whatever is cheaper online.
It's hard to get stuff like this at retail. I had to resort to online shopping to get some action figure stands for my MU figs. I called every comic and hobby shop in town (not really, but enough to not want to call anymore) and no one carried them.
Paying shipping is sometimes a necessary evil for this blasted hobby!