This is one that we used last time.
There is a card you can buy called the Disney Dining Experience (DDE) Card which will give you 20% off all meals and alcohol (except on special days like christmas day).
You have to either have an Annual Pass or be a florida resident to buy one and it costs $75 but you easily make that up on savings!
They do now add a tip 18% usually but can be 20% at v&a for example to your bill. Even if you think of it as just paying for all your tips, $75 is a bargain!