Zinthu is Free for Individual Use AND for up to Three Team Members
You can sign up for a plan immediately after creating an account. You can also use Zinthu under the free plan, invite a few Team members, and then when you are ready, sign up for a premium plan.
You only pay for Team Members for Teams you own (you created), not for Teams in which you are only a member. So, you can be a member of 20 Teams with 250 Team Members, but you will not pay anything and can stay under the Free Plan.
Creating Teams (owning them) is also free, so you can create 100 Teams as long as they do not cumulatively have more than three Team Members. Once you go to invite a fourth Team Member, you will be redirected to a page to sign up for Zinthu Premium. You can pay for one additional Team member at that time, or you can pay for more if you know you are going to invite multiple Team members that day or in the near future.