If you are driving from the Hilton there are two you can go to. The one most tourist use is the Wal-Mart on 192. There is another one on Osceola Pkwy that is more used by the locals.
To get to the one on 192, you would take Hotel Blvd to 535 (thats towards the Crossroads). Turn right on 535 and take that all the way down to 192. Turn left on 192 and follow it til you come to the Wal-Mart (it is on the right side). It is about 4 to 5 miles.
The one on Osceola Parkway, you would take 535 to the Osceola Parkway entrance (it is just a little before 192). The Osceola Parkway is a toll road and it will cost you $1.25 to get there. It is on the left, I would say about 8 miles.
The Osceola Pkwy one is less crowded that the 192 but both have comparable prices.