I got together with 15 of my friends and bought one for us to share. We each had to pay under $50, which made it very attractive. None of us use it enough to justify owning one ourselves, so sharing was the obvious solution.
In any case, 15 sounds like a bit of a logistical nightmare even if you did have that many people in your local friends circle interested enough to go in for a 3D printer.
http://hackerspaces.org/wiki/List_of_Hacker_Spaces
(If there's not one nearby, you could always start one... when I cofounded a hackerspace I met a lot more than 15 new people who wanted to share 3d printers and the like!)