Take a quarter, leave a penny.
At the convenient store there is a take a penny/leave a penny tray. In it are two quarters. You buy all your stuff but you have only one quarter change, and you really need to make an important phone-call. The nearest payphone is across the street at the gas station and it costs fifty cents. Is it immoral* to take a quarter from the tray to make the call?
*Immoral: Demonstrating lack of goodness and correctness in action/behavior; not virtuous.