One of the best feature of owning the Mac or any iOS device with Apple ID is that you can setup your family sharing with your account so that family head can share his credit / debit card purchases within his family members.
Apple allow to setup family sharing up to six members.
Family head with adult age can approve or buy app, songs, ebooks for his family member so that no duplicate purchase would be made of same digital content which leads to financial savings.
Here is what Apple say about it’s Family Sharing feature: Family Sharing makes it easy for up to six people in your family to share each other’s iTunes, iBooks, and App Store purchases without sharing accounts. Pay for family purchases with the same credit card and approve kids’ spending right from a parent’s device. And share photos, a family calendar, and more to help keep everyone connected.
Here is in detail how to setup ‘Family Sharing’: