subscription pricing examples
You will purchase at the subscription level appropriate to accommodate the number of collaborators you would like to work with, total. In other words, when you're thinking about how many collaborators you'll have, think about the number of people you would like to access the full version of Cyborg Llama; CL doesn't care about the number of different projects or groupings you create  it only cares which google accounts need access to the full version of CL.
examples:

You are a teacher with 100 students. You need the 'Very Large Plan' subscription ($40/month; $440/year)

You are a teacher with 50 students at a time, but the students change over the course of the semester. You need the 'Medium Plan' subscription ($20/month; $220/year); this plan supports up to 50 collaborators, but you will be able to easily update the students listed on your plan as your students change.

You are an institution administrator and have 5 teachers that want to use Cyborg Llama with their students. Each teacher has no more than 25 students each. You will purchase 5 copies of a 'Small Plan' subscription.

You are a teacher and want your 25 students to be able to create their own CL projects rather than you creating projects for them. You would purchase 25 copies of a 'Very Small Plan' subscription (assuming each student would use no more than 10 collaborators per project they create).