When we camped at the Fort we drove to Cici's Pizza Buffet for dinner one night. I know it's outside the Disney bubble, but it's the same quality pizza (perhaps even a little better) than onsite, but cheaper, and a buffet so everyone could eat as much as they wanted (we used a Groupon, too, for extra savings).
I also found that the kids meals at the deluxe resorts were a good deal and plenty filling for adults. If you are doing any resort touring it is a cheap-ish way to "eat out." At Captain Cooks in the Poly I really enjoyed the Chicken and Pineapple Skewers with Mixed Greens Salad and Sesame-Soy Dressing for about $8, and my H said the kids cheeseburger meal with double fries (declined the veggie sides) was enough to fill him (we got both with fountain drinks with the kids meals). At the Contempo cafe you can get individual flat bread pizzas off the kids menu for about $8 (includes a drink), at Roaring Fork inside the Wilderness Lodge the kids pasta meal is about $7 (includes a drink).