Yeah, I've used the large plastic bins as well. Though I prefer to mount the puppets on some sort of stand as the bins tend to smush the puppets a bit.
Anyway here is the stand I mentioned earlier. I built this entirely out of 3/4" PVC pipe, joints, and caps for a total cost of about $20. The empty poles at either end of the top row show what they look like under the puppets. I love PVC as it's cheap, easy to work with and doesn't even require any kind of glue or anything. That rack is completely pressure fitted together which means I can pretty easily take it apart to transport it too.
http://i924.photobucket.com/albums/ad83/Puppetainer/Puppet Gallery/Puppetstand.jpg
Hopefully you'll find something in all of the various responses offered here that you can use. Best of luck!