User connectivity

I’d like to find a way to get users of my site to connect with each other in person. Ideally, users would be able to enter their zip codes (or something similar), join a list of people from near by, and then connect with each other. I guess I’m looking for something similar to MeetUp, but that is free for people to start their own local groups.

Anyone know of any plugins or services I can use? I’d be willing to pay a small amount to host the service if need be, but don’t want users to pay.