There's a live audio stream at https://datatracker.ietf.org/group/mimi/meetings/ or the video will be posted later after the meeting. You can also find links from that page to the charter, mailing list, etc, if you want to get involved.
Organizations cost quite a bit to run (mostly a mix of staff and marketing), and have different models for funding it. Some are more closed in participation, asking organizations and individuals to pay anywhere from $5k to $100k to participate, while some charge for the specs they produce.
IETF gets 40% of their revenue from meetings, but has managed to figure out how to fund open participation and open specs.
Having said that, the pricing for remote participants is currently a major topic of discussion.
https://datatracker.ietf.org/doc/draft-ietf-shmoo-remote-fee...