I was going to suggest appear.in, only to learn they rebranded to whereby.com and I see the free level only allows 4 attendees. I have only used it with two people in the past, and at that point it allowed you to pick one sender to be much larger than all the rest. (As I have never used it with more than two I don’t know if it would context switch the large image based on who is speaking.) They charge $50/mo to allow up to 50 people… I wonder if they have a larger free tier for non-profits. (Mind you I don’t know, is Toastmasters actually a non-profit?)