Cydia - An alternative app store for jailbroken devices.
AppReviewDesk - App Review Exchange, Free App Websites , Twitter Marketing for apps.
Fnd - Browse Apple App Store and iTunes on the Web
Review Lancer - Reviewlancer also provide a platform for Developers or Marketers to free exchange app reviews and ratings. Now market your app for zero budget.
AppRecs - AppRecs sorts through reviews in the App Store and automatically helps you filter out inauthentic results.
UserTrue - Free peer to peer app reviews. Give a review, get a review for free.