When I was 18 I worked at Wendys as a cashier. All I would do is keep a quarter or dime of almost everyone’s change I gave back. I would put that extra quarter or dime in a special spot in the register. Once I got 5 or 10 worth of change I would dump the change into the right spot and pocket a 10 or 5. Some nights I would leave with over 50 bucks in cash (a lot to me at the time). No one ever caught on and only twice I can remember people telling me I gave them the wrong amount of change back. I would just act like a dumb kid whom miscounted . I don’t know how nobody at work caught on because I always had a ton of change at the end of the day.