For breakfast we usually eat in the room. I bring or buy bagels, little cereal boxes, muffins, etc and then buy milk, juice, fruit, etc. Besides saving money we also save time since while some members of our family are getting dresses, etc, others can be eating. We're not big breakfast eaters (well, my teen son is a big all the time eater) so this works well for us.
I also bring snacks into the park (fruit, granola or Nutri-grain bars, little packs of peanuts, etc) so when the kid-morning munchis hit we can have a snack.
In addition I buy sandwich fixings and snacks so that we can make a sandwich in the room at least once for dinner. At that point we are so tired that we don't mind a quick, no-fuss dinner (and we just want some food to fuel us when we go back into the park for the evening). When we splurge on a nice meal we know that we've saved $ from a lot of the other meals.
Works for us at least. T&B