Where would the economy of this quadrant of the galaxy be without the entrepreneurial spirit of the Ferengi? What is the foundation for their insatiable thirst for profits? It must be the aphorisms, guidelines, and principles called the Rules of Acquisition.
Rule number 1 is "Once you have their money, you never give it back."
My two favorites are
Rule 34: War is good for business
Rule 35: Peace is good for business.
And the one that has saved me more times than I can count
Rule 59: Free advice is seldom cheap.