Sagemaker charging query

No, there is no charge for users and domains.
Fees will be charged for those listed in the following documents.
For example, there is a fee for instances running on top of a SageMaker domain.
https://aws.amazon.com/sagemaker/pricing/?nc1=h_ls

There is no charge as described in the following document.
https://aws.amazon.com/sagemaker/faqs/?nc1=h_ls

Q: Do I get charged for creating and setting up an SageMaker Studio domain?

No, you don’t get charged for creating or configuring an SageMaker Studio domain, including adding, updating, and deleting user profiles.