Wedding reception in a barn. Know of a alternative to renting $tables? Straw bales, nowear to sit plates?

I am planning a reception in our barn, which is very pretty. I am trying to keep costs low. We will be having about 200 guests for a laid back bbq. I don't want to have to rent expensive tables and chairs. My dad suggested straw bales with old quilts for people to sit on, but then everyone will be balancing plates and drinks. Any ideas of how to make tables, or what I could use instead?