Hi, Cheryl! What a wonderful Grandmom you must be to want to take your Granddaughter to Walt Disney World! I have three lovely daughters who are willing to be your granddaughters any time you feel a need to take more kids to the wonderful World of Disney!
The fee for parking at any of the Walt Disney World theme parks is $12 per day. The four Walt Disney World parks include the Magic Kingdom, EPCOT, Disney's Hollywood Studios, and Animal Kingdom.
As for single day ticket discounts, I have to tell you that these are few and far between. The outlets that do offer discounts, usually do so for only multi-day tickets. One website I go to for discount information is
www.mousesavers.com - they usually list any specials and any legitimate offsite outlets that sell discounted single day tickets. The only single day discounts I see available right now listed on that site are for the Auto Club South (Florida) and students at the University of Central Florida.
The cost for an adult for one day is $75, and that does not allow for park hopping. The price for children ages 3-9 is $63. Ticket prices are subject to change.