Apple App Store - Install apps on your iDevice via the App Store.
UserTrue - Free peer to peer app reviews. Give a review, get a review for free.
Cydia - An alternative app store for jailbroken devices.
AppReviewDesk - App Review Exchange, Free App Websites , Twitter Marketing for apps.
iNoJB - iNoJB, formerly iNoCydia, is an amazing Cydia alternative requiring no jailbreak!
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.