One app to reveal them all
App Permissions is a tool that displays the permissions for all of the apps installed on your Android device, so that you can check for apps that can cost you money or compromise your privacy by accessing confidential data.
You can also search for apps that use certain permissions or combinations of permissions, or use a set of predefined filters, for example to reveal all apps that may cost you money or impact your battery life.
Compare the list of permissions for an app to its key features; there should always be a logical connection between them. A word of caution: you may learn quite a lot about your apps — so be prepared.