When you create a new AWS account the access to Billing for IAM users is not enabled by default.
In order to allow access you have to follow the steps below:
- Login to your AWS account with your root user (email and password)
- Go to the top right drop down ‘My Account’
- Find the section that is called ‘IAM User and Role Access to Billing information’, use ‘Edit’, tick the box ‘Enable access’ and then ‘Update’.
More information can be found in the Amazon’s help page https://docs.aws.amazon.com/awsaccountbilling/latest/aboutv2/control-access-billing.html#ControllingAccessWebsite-Activate