Using an account credit for online store purchases

What specific challenge or problem does this idea solve?

We have a lot of families or pay ahead and have credits on their account.

How should this work?

It would be great if there was a way for a family to be able to use that credit to pay for something they are purchasing from the online store.

Who will benefit (Admins, Staff, Students)?

How will this change impact your daily tasks or overall experience?

I know that you can switch the settings to allow them to "bill to account", but we want everyone to have to pay for the items when they order them.