The paint cans are purchased from the local do it yourself center. Around here (sunny So. Cal.), that is home depot or lowes. Lowes is cheaper ($2.17 but are always out of them) Home depot is $3.19. The keys are free at lowes but they will only give 1 or a few more, if your real sweet about it. At HD they sell the keys for .85. Thanks for all the nice comments.
To cut holes for the handles just punch with a 1 inch circle punch. And then make a slit from the edge of the paper to the hole to clear the handle. Sometimes you can get the cans with handles that come out. But you still need to punch the hole because of the base the handle. Does that make any sense? Good Luck!