The Verge writes Microsoft 365 Business will cost $20 per user, per month. The pricing of the enterprise version is unknown but will probably vary based on the number of users.
Microsoft 365 Enterprise will be available for purchase on August 1st, with pricing dependent on the specific plan and “other factors.” Microsoft 365 Business will be available in public preview on August 2nd, with a full release set for later this fall. Microsoft 365 Business will cost $20 per user, per month.