Here is some  info on 2011 Disney World ticket prices. As you can see, the more days you buy, the less you pay per day.

Park Hopper option: Enjoy incredible flexibility when planning each day’s activities by being able to visit Magic Kingdom theme park, Epcot theme park, Disney’s Hollywood Studios theme park and Disney’s Animal Kingdom theme park on the same day. You can ride your favorite attractions at one park in the morning, then check out fireworks at another park in the evening, or go back to a park you’ve already visited to do something you loved the most. If you want to come and go as you please, this is the option for you.

Water Park Fun and More option: Include the Water Park Fun & More Option to enjoy admission to other exciting attractions at the Walt Disney World® Resort: Select from two fabulous Water Parks, DisneyQuest® Indoor Interactive Theme Park, ESPN Wide World of Sport; Complex or a round of golf at Disney’s Oak Trail Golf Course, a relaxed, nine-hole walking course designed for the entire family. The number of admissions depends on the number of days of the ticket you purchase

No Expiration option: The Magic Your Way base Disney World tickets expire 14-Days after their first use. Electing the No Expiration Option means you are  free to come back and take advantage of unused tickets at any time. Add this to any Magic Your Way Pass and unused days never expire.

You can also visit Orlando Fun Tickets to get great deals on park tickets.