What's the best way to find testers for my new iphone app?

So here we are after busting our back on an app for the past two months. Its a location-based dating app. Its still a bit shaky, but before we put more time into it, I really want to know what my target audience thinks about the app and its functionality. It's been built for folks between 18-30 years of age

Basically, I need to go out and talk to these prospects and watch them use the app and prioritize future functionality (or remove functionality :))

I've been told by friends that the best way to do this is to reach out with an ad on craigslist. This route costs about $10-25 per hour per person. We're doing all of this on a shoestring, so was wondering if you folks know of a better way to get a focus group put together on the cheap, or for free. (I am working with friends, but am worried about bias from that quarter)

Thanks so much for your help.