At the gate, the per-person per-day price is $79 adults (ages 10 and older) and $68 children (ages 3—9). You can buy tickets at the Transportation and Ticket Center (TTC) in the Magic Kingdom, from booths at other park entrances, in all on-site resorts if you're a guest, at the Disney store in the airport, and at various other sites around Orlando. You can also buy them in advance online—the best way to save time and money.
If you opt for a multiday ticket, you'll be issued a nontransferable pass that uses your fingerprint for ID. Slide your pass through the reader, just like people with single-day tickets, and also slip your finger into the V-shape reader.