Go to Profile > Settings > Your company > User management
When adding a new user:
Click on Add member
Enter their email
Scroll down
Click on Can manage shifts
Scroll down
Click on Advanced settings
Tick Hide costs for this user
Click Save
For an existing user:
Click on Edit
Scroll down
Click on Can manage shifts if not already selected
Scroll down
Click on Advanced settings
Tick Hide costs for this user
Click Save