Yeah I definitely agree with you! I know some people view free forum hosting as a bad thing and unprofessional but I don't view it like that.
Same here. I remember Atrium on Zetaboards (before Zetaboards was bought out by Tapatalk). That's a good example of having a good, active forum on a free forum hosting.
Free forum hosting is a great way to get started and test your abilities as a forum owner, without having to fork over a bunch of money up front.