Joe asks 'What cheap case can be used for small equipment?". If we're not talking about fragile equipment, I know a few people using these Plano 4 Pistol Foam Lined Cases. These aren't your waterproof air tight 'Pelican-Like' cases, but they still offer a fair amount of protection. With an internal dimension of 16" x 10" x 6", these pistol cases are large enough to hold monitors, portable audio recorders, microphone systems, battery chargers, and more.
Typically these run between $25-35 dollars, but it's currently on sale today for under $12 dollars. Jump over to the page and you'll find other customers sharing images on how they use it with their camera gear (found here).
Plano 16" W X 10" H X 6" Deep Molded Case with Foam Liner
For smaller equipment that I feel can take a few bumps, clear Organizing Tackle Boxes work great. The clear boxes take the guess work out of finding gear, all without having to open the box. You can organize and label areas such as 'new' or 'used' for batteries.
Example of how I use these cases
The trick is finding a good set, and the ones I use are also from Plano. Not just durable, but 3" deep to hold fairly thick camera accessories such as LP-E6 Batteries. Overall storage dimensions are 10.5" W X 7"H X 3" Deep, and these run under $7 dollars (found here).