Use the same things as for the planter or use construction paper, cloth or even a paper bag you put stickers on. Coffee cans make great coin banks. Decorate any way you wish and cut on x in the lid. Put the lid on and now you have a bank. Actually any can or container with a plastic lid can be made into a bank.
Coffee cans make great canisters.
Use to store rice or other food. I'd put a plastic bag inside to make sure no coffee flavor gets into the food. If you decorate the can it looks a lot more attractive than a plastic bag. How about decorating a small can. Rust proof the inside to hold toothbrushes or hair brushes in the bathroom.