How do you bypass the family purchase credit card and use an iTunes card instead?

Jons Mama,

If the person making the purchase has a credit balance, the purchase will go against that rather than the Family Organizer's credit card. See information in his document:

Family purchases and payments

"After you set up your family, any time a family member initiates a new purchase it will be billed directly to your account unless that family member has gift or store credit. First, their store credit will be used to pay the partial or total bill. The remainder will bill to the family organizer's card."