What if a league does not fill?

I joined one of the free leagues. It does not appear that anyone else is in the free league; at least no one else is making any transactions. I also have joined an auto 70's league because it seemed as if it had the best chance to fill. If it does not fill, do I get a credit? And what are the chances of leagues filling at this point? The league I joined now has 5 owners.

The free league may or not fill. 70's league will probably fill at some point, but you can always remove that team from that league, and switch to any other autodraft league of any era you want.