Caterers always charge on a per head basis. When figuring out what you can afford, divide your approximate number of guests into the amount you have set aside for catering to arrive at your budget.
Dinner is the meal caterers are most commonly called for, but the brunch or breakfast variety will cost less. Caterers can either be Formal (staff-served), or Casual (self-serve), and can range from the traditional beef/chicken entrée to the more exotic tastes.
The possibilities are endless, and it all depends on how you want to approach your wedding or event. Don’t forget any special needs or culinary preferences some of your guests might have (such as vegetarian or kosher).
If you have questions please ask your caterer of choice.