Love WoW, but hate the monthly fee? Well, WiWStatus.net may be your answer.
A free server might be nice, but somehow I don’t think playing with 30-40 people on the entire server is going to be any fun. It’s hard enough to find groups for certain instances as is. 
Oh, and I’m almost certain that this will violate Blizzard’s Terms of Service. So, I wouldn’t suggest trying it out unless you are no longer paying for WoW. 