Many people like Golden Corral. At roughly $10 per person all you can eat for dinner (lunch is a bit less) you aren't going to get much cheaper that that!
Bahama Breeze isn't too bad, nor is Pebble's. There are a number of nice restaurants on Sand Lake Rd in the Dr. Phillips area. If you like Indian there is a great restaurant in the K-Mart plaza on Turkey Lake just as you cross over Sand Lake.
If you like Asian, primarily Vietnamese, but not strictly so, head to downtown Orlando on Colonial (50) there is a complete strip there of great little restaurants, a couple of which are Cuban. It's about 20 minutes or so from the WDW area.
If you have the facilities for it, Publix has really nice cooked chickens in several types (BBQ, Lemon, Mojo, etc.) and a great selection of prepared salads and sides. You could do a cold picnic dinner/lunch.
In general the further you get from the WDW immediate surround, the less pricey the meals are. The Ale House is one exception. It has pretty basic food but the portions are quite large and you won't leave hungry. It has a pronounced sports bar atmosphere though, if that is a factor for you.