We have AP's for WDW so will be able to park for free.
However, do I remember (I may be making this up in the hope that it's true!!) that SW do a parking deal which is less than two days parking? So, if you are going two or three times, you can get a parking ticket that will cover all of your visits for about $17
Re: Parking deal
This is all I see on the SeaWorld website
Nearly 6,700 spaces are available for vehicles. Spaces are available to cars and motorcycles for $10.00 - recreational vehicles for $12.00. Preferred parking available for $15.00. Platinum Passport members receive complimentary preferred parking. 1 year and 2 year Passport members can park in general lots for free, and pay only $7.00 for preferred parking.
We have a platinum passport (covers all of the Anheiser Busch parks) so we get to park for free.