I found sticking to 4 or so things makes it cheaper and easier too. If you are doing a BBQ perhaps just snags/bread. Agree with the fairy bread/cupcakes and then maybe some popcorn (do you have a popping machine or someone you can lend it from) as an activity even so making popcorn necklaces etc. Something out of puff pastry can be cheap as a savory too - so pinwheels with cheese/ham or just pesto. Squares with a few olives and some cheese?
I think keep it simple as often there is way too much food at parties and often it gets left out and goes to waste.