We have a Managing Agency and 20-30 "Sub Agencies".  I have read and think I understand User / Profiles / Groups.  

My questions are this: 

1.  Can we limit the number of Contacts/ Leads that an Agency can add?  

We will let them have access to our MASTER CRM, but want to limit their usage to only 100 contacts in their subscription.  If so, how can this be done?    

2.  Is there an existing module to help facilitate billing for this approach?