How about hanging out at your local Starbucks, and offer to buy people a cup of coffee if they spend 10-15 minutes checking out your app and giving you some feedback? A bit scary for the introverted hacker, I admit. But I bet you get enough people to take you up on it to make it worth your while.
Why not put an ad on Craigslist looking for testers (for free) and they can email you for a free download code from itunes? A lot of people would try it if they thought they were getting something for nothing.
Alternatively, post free download codes here and you will also probably get a lot of people glad to install the app and poke around.