What are Disney Dollars?

The designs of each bill usually go along with a general theme whether from the 80th Birthday of Mickey Mouse to the celebration of the individual Disney parks throughout the world. 
Disney Dollars have come in four denominations:
The $1.00, $5.00, $10.00, and $50.00​

 In 2007 Disney Celebrated 20 years of Disney Dollars.  (as seen belowt). The most recent bills theme is the "Mountain series" celebrating Disney theme park: Mountain rides, Splash Mountain, Space Mountain, and Big Thunder Mountain.

Disney Dollars were retired May 14, 2016
Disney Dollars are a form of corporate scrip or tokens or currency used at Disney theme parks, Disney Store, Disney Resort Hotels, and at one time certain parts of Castaway Cay, the Disney cruise-line's private island.

    It is worth dollar for dollar.  Being backed up by real money. The bills can be used pay for purchases or debt. According to the 2013 series Disney Dollars
2007 $1 Disney Dollar - Ariel
Disney Dollars may be spent or collected and saved as souvenirs and are redeemable at any time before or after any period of inactivity
 People may keep it as a souvenir or spend it like cash at theme parks, or stores that Disney maintains.  
    The Disney Dollar shown is the 2007 Disney Dollar, Each bill is different in comparison to previous years. Each bill has a Serial number and letter differentiating each bill. 

2007 Little Mermaid Disney Dollar