If you're on a budget you might want to eat your biggest meal at lunch time (cheaper but just as good) and then snack at a counter service for dinner. Thats how we do it when we want to save a buck or ten. Here are the places we've eaten that I would go back to on a budget:
MK:
Lunch at
Liberty Tree Tavern is little known, pretty cheap and yumm-O!
Dinner at
Caseys or
Pinocchio's or
Columbia Harbour House
MGM:
Burger and Shake at
Sci-Fi there more expensive food is el grosso anyway!
Appetizer and dessert at
50's Primetime
DD:
Wolfgang Pucks Express (Your best choice for great food cheap! There are 2 locations and they are both great- the one across from the Virgin Megastore has alot of the same items as the actual sit down WGP Cafe for a whole lot cheaper and has fresh desserts, the one in the Marketplace is great too but has prepackaged desserts-still great.)
Earl of Sandwich-$5 bucks- nuff said
EPCOT:
Edited to add my absolute favorite -don't know how I forgot this one! Morocco CS-Lamb Platter or Sandwich!!!!!
Sunshine Seasons is great and has lots of choices!
Be sure to pick out at least one World Showcase Restaurant that appeals to your group and just order within your budget. Maybe share entrees or just do apps. and desserts.
Also nearby is the Boardwalk Resort area with:
ESPN Club (priced more like a Chili's or Friday's & big portion sizes)
Beaches and Cream -their sundaes are about $7 bucks and with an order of fries its a meal!