We do similar to crisi and pigpen suggest. However since we hit the parks very early we would wiat for a late lunch. Anyway we eat cereal, breakfast bars etc in the room around 7 am. By 11:30 we are ready for a break so I make a PS for lunch (usually a buffet). Then we can usually eat very light for dinner (counter service) or grab a WDW snack and then if we are hungry back in the room I bring plenty of "healthy" snacks (yogurt, cheese sticks, carrot sticks etc).
As for prices It really depends on where you are use to eating. We don't eat at McD's often at home, so why would I pay 25% more to eat at the one at WDW? The burgers at Pecos Bills are much better.
For example a Mc Donalds 4 piece nuggest happy meal at AK is 3.79 . The 1/2CheeseBurger with fries is 6.49.
At Peco's Bill's the kids meals are 3.49 and the 1/2 Cheese Burger and fries (or carrots) 6.59.
My favorite at Peco's Bills is the Kit Carson Chicken Salad for 6.49. I would pay that much for a comparable chicken salad at Chili's or Applebee's.
Other less expensive ideas inside the parks
Epcot
Beef curry over rice at Yakitori House $5.95 ... all meals there are in the 5-8$ range.
Electric Umbrella .. Burger andd fries 5.59 , grilled chicken and fries 6.59
MGM
ABC commissary...
Fish and Chips - $6.29
Chicken Yakitori - $6.59 - (skewered chicken, marinated & grilled in sweet teriyaki sauce, served on steamed white rice with Asian slaw)
Feijoada - $5.29 (Brazilian entree of stewed beef, pork and black beans with steamed white rice)
AK
Tusker house
Grilled Salmon served with rice and fresh seasonal vegetables $7.99
1/2 Rotisserie Chicken served with garlic mashed potatoes and fresh seasonal vegetables $7.99
At least in the Atlanta area these prices are very comparable.
As my DH just pointed out. Trying going to Six Flags or some other amusement park. A burger alone is 6-7 with out the toppings bar at Pecos Bills. He even pointed out that while the buffets are a little more compared to ouside the world, whre else can you dine with Pooh or Mickey. We spend about 70-80 on a big meal for our family of 4 at WDW and 20-30 on counter service(2 adults, one teen that is adult prices and a 5 yr old). Not bad in my book, especially whne I look at the prices at other tourist attractions.