Does anyone know if AutoDesk APIs are paid services?

We are able to authenticate users through 3-legged oAuth2 with full scopes but the access token doesn’t get us anywhere. We attempted to get a list of hubs for the Autodesk that our customer is running. But we are getting no accountId and messages about not having permission to access this API. The Autodesk userAccount being used for this is an admin account in Autodesk and it also grants access to the Autodesk Platform services which is the developer area.

Will appreciate guidance on this.

Thank you