Yeah, 'cheap' at Disney is very relative.
At WDW - I think Boma, Kona Cafe, and most of the World Showcase restaurants to be a very good value. They aren't 'cheap', but for what you pay the quality is quite good. If you are willing to splurge, Artist Point is excellent. You can check out menus at Allearsnet.com to see prices. If you want character dining, the breakfast at Crystal Palace is pretty good.
At DL - Storytellers Cafe in the GCH is a very good value. The breakfast buffet is around $20, but it's excellent and will fill you up until dinner with perhaps an ice cream break in between. Lunch is a la carte, but portions are big enough to share. I haven't had dinner there yet. In DTD, there are lots of options. I like ESPN zone, their portions are very large.