Lisa, welcome to the Disney Parks Moms Panel!
You are able to use Disney Gift Cards to purchase food and merchandise at the Walt Disney World Resort at all resort hotels, throughout the Theme Parks, and at most Downtown Disney merchants. This is a wonderful way to budget your expenses.
While visiting with my own family, we typically take advantage of the Disney Dining Plan to budget our meals and snacks. We have also used Disney Gift Cards as well, especially while eating around the world at events such as the Epcot International Flower & Garden Festival and Epcot International Food & Wine Festival Presented by Chase.
Disney Gift Cards are a great way to track your souvenir spending, especially with children. For each trip, we purchase Disney Gift Cards online. There are over a hundred different designs so each child can have their favorite character while making it easier for mom and dad to keep their cards separate. You can load each card with the same amount of money so each child has the same amount to spend. My children understand when the money on the card runs out, they are unable to make any more purchases. This tends to help them make smarter purchasing decisions.
Have a magical day, Lisa!
~Rachel