Here's a novel idea. You can sign up at a new website, FuelMyApp.com, and get paid apps for free. In exchange, you agree to review the app on iTunes. Of course, you aren't obligated to give a positive review. The way it works is that you sign up on FuelMyApp.com and give your PayPal e-mail address and iTunes nickname. Then you select an app from the website and pay for it as normal. Once you've tried it, then you review it on iTunes. As soon as your review is published, FuelMyApp automatically credits your PayPal account for the amount you paid for the app.
This is good for you because you get to try apps without paying for them. And it's good for developers, because new and unknown apps don't languish in the App Store without any reviews. Developers submit their apps to FuelMyApp and specify how many reviews they want and whether to make the offer available globally or in a particular country. They're also able to track the progress of the reviews in their account. The whole thing seems well thought out.