Are you want to make a forum? Afraid on the cost? No fear again. I just found this site. I think it is a great site that provide free forum, hosting, unlimited space, secure, automatic update, free image hosting, support on chatting, gallery, calendar, portal, game and many more; free [sub] domain and free skin for your forum. That's all free for you. You do not need to do something. Just sign up, next, next and done. :D
It is Forumotion that give the great free forum. This forum available on phpBB2, phpBB3, punBB and invision.
So what are you waiting for? Just have your own forum..