You ought to set up next to your local Coinstar coin machine and cut out the middle man when the masses come in to cash out! :)
Those machines really do take quite a slice from those that don't realize or care exactly what is going on there. I wonder if in your area banks also charge or force you to either roll or deposit coinage in a coin counting machine that takes a large cut or not? Wow - Coinstar charging 10.9%, glad I bought a coin sorter.