I've tried bringing nutritious snacks along and Boy does that idea go out the window when you come across your first Churro Cart!
Churro's are up to $2.75 now, I believe.
Soda is prohibitively expensive, if you can get your people to drink juice boxes you will save a Ton. Bottled water is as expensive as soda. I bring a filtering water bottle and fill up at the drinking fountains.
It's tempting to think that you will save money and eat off property but it's Darn hard to leave the park in the middle of the day! Our best strategy was to eat a very light breakfast (at the hotel), our main meal in the middle of the day (3 pm or so) and smaller snacks in the evening. We found if we ate our big meal at night we were all very sleepy afterwards.
Cost wise...how much money should you bring? How much do you Have?
I try to budget about 25 bucks per person per day for food but it usually runs a bit (or a Lot) higher, depending on impulse munching. This
doesn't include any Character meals or full service restaruants - the Blue Bayou will run you about $20 each for lunch and up to $35 each for dinner. Character meals are in the $20 range. (I'm going to have dinner/lunch at the Blue Bayou on my birthday. I've allotted about $100 - 2 adults and one 13 yo that eats like one - drinks, appetizer, main course, dessert, tip...spendy but for me, worth it!)