It is very important to determine how much your budget is for the particular event or function you will be hosting.  You have to discuss this budget with your caterer before you proceed into hiring their services.  Of course, along with budget, the caterer needs to know how much people this budget of your will be served to.  Your budget will only be as good as the number of people it serves.  Even if your budget seems big, if the number of guests that needs to be served is also big, then simply put, your overall budget per guest goes down.