Excellent reasonably priced ($15.00-$20.00 per entree) restaurants that we enjoy are, Grand Floridian Cafe (our favorite restaurant of all), Olivia's, (excellent food and wonderful service), the Plaza Restaurant at Magic Kingdom (excellent sandwiches, shakes and ice cream), Whispering Canyon Cafe has an "all you can eat" choice of good food, and would be LOADS of fun with a large group like that, Yachtclub Galley is also excellent and has a very nice breakfast buffet, while often getting mixed reviews, DH and I enjoy Big River Grill and Brewing Co., the Hazelnut Crusted Chicken for $15.99 is very good and the portions are very large, at Epcot, the Biergarten in Germany is a nice buffet with polka music to eat by.
While they are two of our favorite restaurants, Le Cellier and Artist Point are both quite a bit pricier. Also, Chefs de France has excellent food, but I think entrees will run higher.