If you're staying off-property, parking at the Disney parks is $14 per day. If you plan on visiting more than one park per day, keep the parking stub from your first park, and show it when you get to the gate of the second park. They won't charge you again for parking.
If you're staying on-property and want to take your car to the parks, just show your parking permit from the hotel at the park gate and you won't be charged to park.
HTH!!