Hi there, Tina!
The good folks at MouseSavers.com have developed a very comprehensive list of historical Walt Disney World discounts over the last several years.
This list can be found at:
http://www.mousesavers.com/historical-information-on-walt-disney-world-resort-discounts/
Please note that this is not an official Disney site, and that all information is posted by third-party individuals.
In the past, while it is rare, there have been substantial discounts offered during the month of May. This is a pretty busy month at Disney, thanks in great part to the number of Spring Breaks happening during the month, and the number of families that take advantage of this family time. But you will find in that list both free dining and "Kids Stay and Play Free" promotions.
Keep an eye on the
Disney World Special Offers page for the latest news for good deals; you might also want to subscribe to the
Disney Parks Blog for breaking news.
Happy planning!
See you later, celebrator,
-Deborah B.