Hi there, Kelli!
What a great idea. Giving the children their "own" money will definitely minimize some of the hassle of keeping everything "even", and it will actually give them a little lesson in budgeting (shhhh!).
Right now, the kiosks in the
Arcades take cash, credit, or your Key to the World Card, which you will receive at check-in. You might consider putting a balance/limit on each child's Key to the World Card; this way, each child will only have one card to handle, and it can be used all over the Parks, including at the Arcades.
Just let the Cast member know at check-in, and s/he will help you set things up accordingly.
Have a great trip!
See you later, celebrator,
-Deborah B.