Web conferencing isn't hard, but it does require a decent umph. Things like polls, screen sharing, audio, video, chat, recordings, closed captioning, etc. Big Blue Button is a solution to solve that. If you run Greenlight for your conferencing (or want to), you'll need a BBB instance to make it all go.
Thankfully for you, I've done all the hard work to get BBB up and going. It can scale to 50-100 people before it takes a nose dive and provides all the bells and whistles. The servers are in California, but if you need one on Mars and don't like the latency of California, I can probably swing that too.
The cost is $6/server/month, billed monthly, and subject to my reasonableness clause.