Adding a day to a 3 day ticket?

[theone74733]

I am planning a trip to WDW and was going to get 3 day base tickets with no park hopper. However, we have an extra day built in the schedule to hang by the resort/visit Disney Springs, but was thinking about adding a park day if needed once we get there.

How much would the cost be to add the extra day to the ticket? I don't know if I wan't to pay for 4 days if we get there and decide not to go to a park on one day.

 

[purple figment]

$35 plus tax