Yeah, using the site chat would be fine as well.
As a free (as in beer) alternative, Google Hangouts has a free group feature with up to 10 video participants (or 150 chat participants) for free: https://support.google.com/han...answer/3111943?hl=en.
And if people wanted to do a teleconference at some point, we could simply record it and publish it here (via YouTube), so that the rest of the community could enjoy it as well.