The Wayback Machine - http://web.archive.org/web/20040214020046/http://icp.meetup.com:80/faq/single.jsp?faq=is_this_free
Is this free?

Yes, Meetup is a free service. Some venues pay Meetup to be listed and to help coordinate events. (Note: We NEVER force a Meetup to be at a particular venue. Meetups only happen at places that the people vote for.)