1. a new variable. lets call it moneyint. If the player picks up money, moneyint = moneyint + pickedup
2. another variable. lets call it progressint. when player beats a level, progressint = progressint + 1 and when they try to go to another level check if progressint is equal to 1
3. when player tries to get in a car, if their moneyint is greater than carcost, then the door is opened