Chip and Dale also appear at the Garden Grove at Swan/Dolphin.
Can't quote prices right now, but believe Garden Grove is less expensive. And you can almost always get a $25 certificate from restaurant.com for $2-$3.
We went to the Garden Grove Dinner buffet last October and Chip, Dale, Pluto, and Goofy were there. However, please note that they do rotate characters on some days so be sure they are going to be there the night you plan to go.
Food was much better than I expected. My wife & I were pleasantly surprised. And kids loved the characters.