In Project.co we have 5 user roles:
Creator Admin (PAID)
Creator Plus (PAID)
Creator (PAID)
Collaborator Plus (FREE)
Collaborator (FREE)
Anyone who is assigned one of the 3 "Creator" roles above is a user that needs to be paid for.
Creator roles are for people who are typically managing projects and moving work forwards. Whereas Collaborator roles are for people who you want to work with on projects such as clients.
See more about user roles and permissions here: