They are still fair in price. Like Soundgod said, Six Flags charged $15 this year and will not doubt go up next year as they do every year. WDW is still cheaper or in range with normal park pricing for parking.
This only applies to people staying off site and going for the day. I, like most of you, stay on site. Parking is free. Other theme parks, or most of them anyway, charge you for parking regardless of where you stay.