I'll assume you have no car,and are 'stuck' on property
dtd- Dh loves earl of sandwwich-the kids and I

wolfgang puck express,and don't forget to try the express restaurant on the west side,they have a different selection at good prices- I can split 2 meals and between myself and 2 kids usually-or get soup for like $4-
Hotels have some cheaper options- downstairs at the polynesian,they have a large,inexpensive selection of foods-
Epcot center-Sunshine food fair has huge selections of cs choices, cheap,and some of the kid meals are big enough for my meal! i.e.,one counter sells baked chicken- kids meal is like 3.99,comes w/drink,applesauce,chicken leg,mashed potatos and cooked veg.!
or some of the "quick" places in the countries area- like the cs at Morocco,or Norway,or Mexico,mmmm! My kids love to split the nachos at the outdoor Mexico place, like 7.95- they're HUGE,it's a full dinner for both of them!
Check out Columbia harbor house at MK, lots of low cost, mmmm choices-family size chicken salad is $7-
the thing is, most menus don't tell you how big something is, if you like a cs menu,ask the cashier how big an item is,and if you need more, you can always order more,or get a snack later-
our family of 4 rarely spends more than $50 a day on lunch,dinner and snacks, and there are lots of choices,depending on where you stop!
We liked Pinnochios village house - small pizzas,salads,soups,etc...
Go to allears.net,they have menus for everything-you can eat plenty of good food without going broke,I promise!
We don't do dining plan,but we do take the kids to one sit down character meal-that suits us all.