it mean you shouldn't waste money because you have earned it and you should not want to throw away something you earn right away.
It means that if you save a penny,you earn that penny when you really need it to spend.
Benjamin Franklin
DIBHV
What Benjamin Franklin ment was any penny you don't waste is the same as earning a penny. Pennies don't mean much anymore, so think of it as $10. Basically, not wasting $10 is the same as earning $10.