AppShopper - Mac Apps, Mac App Store, iPad, iPhone and iPod touch app store listings, news, and price drops
AppRecs - AppRecs sorts through reviews in the App Store and automatically helps you filter out inauthentic results.
Apple Sliced - Apple Sliced searches the Web for the lowest prices and uses only Authorized Apple Resellers, so...
Fnd - Browse Apple App Store and iTunes on the Web
Magicube - Looking for the best Windows 10 apps? Check out these Universal Apps for PCs and Phones.
Cydia - An alternative app store for jailbroken devices.