Earn cashback shopping on Amazon and more whilst building savings for children Kidstart(it's free). You don't need to add a child's details to start earning cashback - you can add them later. Log in and click KidStart’s link to visit your shop of choice. Your visit is then tracked and an amount is put into your KidStart account once the transaction's processed. Once you've reached the £10 threshold, you can withdraw your cash. Before you take the money out you must add a child, enter their name and date of birth, then link that profile to a Child Trust Fund, junior ISA or bank account (though this doesn't have to be the child's - it can be your own current account).