"If you are good at something,never do it for free."

This is one of the most famous dialogues by the Joker.The dialogue was used in the second movie i.e. "The Dark Knight".This dialogue has a meaning that everyone must understand.One should not let his talent go waste.If a person is good at something everyone needs the person to do that thing for them with that perfection with which he does that for himself.So,if everyone needs him to that thing for them why should he just provide them and not himself as well?In some cases people start taking advantage of your talent and hence,they just use you and when you realize this thing,you feel like you have been fooled.So,instead of that if you make your talent as your profession then you will be successful in that.Hence,you will make the best money out of it.