I am like you. We have a huge family, because they all live in town.. Blessing and a curse..
Here are some of the least expensive things I have done.
Grilled Hot dogs and sausage wraps, huge tray of raw vegetables and dip, fruit salad.. just cut up, fresh fruit, chips, lemonade and Iced tea. Cake..
Pizzas delivered.. Call your local place and see if they will give you a deal..
At our neighborhood Pizza place sometimes, we can get large Cheese or 1 topping pizzas for $5.99 each.. Sometimes a Major Pizza company will sell them for $8.99 for a large pizza.
You make a huge salad, Ice Cream and Cake..
Popcorn for snack..
I once had fried chicken made at Churches Chicken (local owner stand) for .69 cents for each leg and .89 cents for breasts.. I made a green salad, a potato salad, and a pasta salad.. I purchased rolls. I kept the chicken in a cooler (no ice of course) to keep it warm..
BBQ chicken is easy to make and if you get a good price on chicken.. it can really be a great options..
I also would not hesitate to accept any food that people offer. In our family every one asks, What can I bring? I take them up on it.. They love feeling like they helped out..