Since the 2.0 update, each player has the possibility to choose one of the three classes for free ;
Tycoon : 10% more income from all money buildings, and 10% more defense from defense buildings
Agent : regain energy 10% faster (3 energy every 53 seconds)
Enforcer : regain stamina 10% faster
After choosing a class, the player can pay 150 golds to benefit from all three classes (he then becomes a "Goodfella").