When we went 3 years ago, I pre-purchased a "deal" that brought the price down by nearly half. I don't know if it's still available, but well worth researching within their website. It may be under "local" deals. If it's there you'll find it. Good luck!
Just looked at the site, go to Tickets & Passes, what I'm talking about is the EDGE card. If you're nice with them over the phone, you can buy it even if you're not from the area.