If we can avoid the sit-down meals (we sometimes give in to temptation!) myself, DH & DSs (5&3) make due on less than $100 a day.
Bagels or (Mickey Magic!) cereal in the room beofre heading out
Lunch - counter service, DH & I each get a kids meal or split an adult meal, DSs share a kids meal
Dinner - DH & I usually get our own adult meal, DSs share a kids meal again
If there aren't any 'meal deals' we each get a burger (or pizza or whatever) for each, split one order of fries (or garlic bread or whatever) & drink water
I was are jonesin' for caffeine, I'll get one Coke for us all to share, otherwise we just re-fill water bottles all day!
Before our last trip I bought each DS a Buzz Lightyear water bottle on a strap at the
Disney Store (about $6 each). They loved them and carried their own water for 5 days without complaining since the water bottles were so cool!
By doing all this, we had food $$ left over most days for Dole Whips, Mickey Ice Cream, and souvenier buckets of popcorn!!