i dont like asking people for money, so thats why i decided its bring your own food/booze... everything else is there... a grill, water/pop, entertainment and activities.
You don't even have to bother asking for money. Just put a pitcher out by the grill with a sign that says "donations to cover cost of booze & food." Unless you have cheap friends, you'll almost always end up with more money in that pitcher than you spent on a keg and food.