Microsoft does not charge additional license or subscriptions for external users of your Dynamics 365.
Here are some products that provide portal functionality for Dynamics 365:
Dynamics 365 Portal
In September 2015, Microsoft acquired Adxstudio which had long been providing a portal for Dynamics CRM and a less powerful, free version under the auspices of Microsoft.
Microsoft used Adxstudio as the basis of its latest portal product, Dynamics 365 Portal which is available for Dynamics 365 users as part of the Plan 1 subscription bundle.
Here are the steps to activate a Dynamics 365 Portal.
Dynamics 365 Portal is not available to run on premises.
The Portal Connector
Pavliks offers The Portal Connector for Dynamics CRM based on Telerik Sitefinity. The Portal Conne…