Microsoft seem to be pretty on it with making sure kids can't sneak purchases past their parents. Not only can you choose whether to allow them to purchase items or not, you can also add content restrictions, put money in their accounts to allow them to shop with your restrictions in place, set adult approval settings in place for items they want to buy, and request to be notified via email each time they make a purchase, so you can see what they're buying.
To turn on adult approval for purchases,
press the Xbox Guide button on your controller and go to Settings
. Head to Manage family members
again and then select the name of the child or children you want to use this feature with. Select Privacy & online safety
, then Xbox Live privacy
and View details & customize
, then Buy & download
. From here, you can turn on the Ask a parent
option. It's worth bearing in mind that this works for everything your kids want to buy in the Microsoft store, except for items they buy with gift cards or money in the Microsoft account; these purchases can be monitored with the usual shopping restrictions.
If you want to give your child some amount of autonomy in terms of what they choose to purchase, you can add funds to their account directly. Head back to the family page
on a browser and select Spending
from your child's summary menu. From here you can toggle those Ask a parent
settings mentioned above, but from here you can set it on Xbox and Windows. You can also Add Money
– your kid will be able to use this to make purchases, but only within the content restrictions you have already set out. Underneath, you can see their purchase history and keep an eye on things. Speaking of keeping an eye on things...