I think discounts are pretty much a thing of the past other than DVC, AP and Disney Visa. It is always worth asking.
No discounts, but one of our favorite's is Earl. We split a sandwich for about $10 and leave happy! Chicken Guy has reasonably priced salads that are delicious. We've eaten at the take out window at House of Blues in the past (did not this trip) and enjoyed nachos. All are great food values IMO. Enjoy!