Well since youve done three, you should have a pretty good ideal on the time it will take to make one. Let the group view the three youve made and tell them that you should be able to do this with x hours of recording time and x hours of editing and getting a finished project out the door and quote them your hourly rate. As on a roll pointed out they will be fine with it unless it goes way over. Whats way over? Usually a 10% overage is acceptable. Since you are just starting out, I would not charge any overage just to keep getting your feet wet and more name recognition.
