A brief history of Walt Disney World ticket price increases
[Philip Lelyveld comment: and still on many days the parks are sold out!]
But for a real shocker, take a look at the price of admission on Day 1: In October 1971, a one-day ticket to the Magic Kingdom cost just $3.50.
That may seem like next to nothing, but at the time, both Disney World and Disneyland in California sold books of tickets guests needed to get on rides. Each attraction was rated A–E. An A-ticket would get you a ride on Cinderella's Golden Carousel, while the most popular attractions, like Space Mountain and the Haunted Mansion, were E-ticket rides.
Disney dropped the ticket book system by 1982, but even then, the price of admission was still just $15 to get into either the Magic Kingdom or the newly-opened EPCOT Center.
See the full story here: http://www.mynews13.com/content/news/cfnews13/on-the-town/article.html/content/news/articles/cfn/2014/2/27/disney_ticket_price_history.html#chart