My kids (9-year olds) each got a Kindle for Christmas (thanks Gramma and Grampa!). It looks like even for them to "buy" free books, this is how I had to set them up:
- Create an Amazon account for them
- Manage Account, 1-Click Settings
- Turn on 1-Click for the account
- Add an address
- Click the link to make it the 1-Click default address
- Make this address the billing address
After this, my kids were able to "purchase" free books (and gift cards can be added to their balance), all without requiring a credit card number. Thanks, Amazon for making this so simple! 🙂