In the beginning of Monte Carlo, we find Selena Gomez living a comfortably upper-middle-class existence, which is to say, in the world of Hollywood, poor. And because she is poor, she has to slave away in an adorable restaurant where the patrons are polite and when her parents send her on a vacation to France she has to stay in a shitty hotel where the sockets don't even work right. OMG! The injustice! It is hard to be poor, and therefore Selena Gomez is unhappy.
Luckily, it's not long before Selena Gomez stumbles into an unlikely Prince and the Pauper-ish scenario in which she is transported into a world of immediate entitlement and astonishing largesse! In this world, Selena Gomez and her friends fly in private jets to resort communities, have many pairs of shoes and dress like pretty princesses, thus receiving the "vacation we deserve." Therefore, Selena Gomez is happy. And even though the man who likes her for who she is and not the vast amount of money she seemingly possesses does not know who she really is and that she does not have vast amounts of money, he doesn't like her for that anyway and so it will not be a problem. Everyone will learn life-lessons about the incredible power of money, and then they will be happy.
Now, if you'll excuse me, I'm off to find my fabulously wealthy body-double.