Pixie:
The terms 'play for' and 'represent' aren't synonymous.
Suarez has a particular talent which means that he can be highly paid but only during a fairly short career. To secure his future, it makes sense for him to simply 'play for' whichever club will pay him the most money.
However, if he had the right to choose between 'representing' different national teams (which he doesn't anyway), it has nothing to do with money. He would logically choose to represent the country where he was born, where he was brought up and where most of his family and friends still live.