There's a lot you can do at Disney World that doesn't require you to shell out money to go to the parks. First of all (which is popularly mentioned), you can go to Disney Springs. There's three noticeable sections: Marketplace (traditional Disney stores), the new Springs area (like an outdoor mall), and West Side.
If you don't want to eat at one of the restaurants in Disney Springs, you can always make a reservation at a restaurant at a Disney resort! When you drive to the front gate of that resort, the security guard will let you in if you have a reservation.
There's also mini golfing (must pay admission), the Wide World of Sports (must pay admission), not to mention all of the amenities at the resorts! (But you do have to be a guest at the resort to use it's amenities.) A specific resort's amenities depends on which resort it is. Port Orleans has fishing, but Grand Floridian has a spa, etc.