Android App Store
Here we have Android App Market some of these are totally free means you do not have pay to download any app
Download apk directly from Android market even without Google play store account, APK Pure is a totally free APK downloader for Android phone and tablet
The project's aim is to promote free and open source software on the Android platform. AndroBranch organizes apps in an attractive, Google Play-like arrangement with the ability to view apps by popularity.
The F-Droid Repository is an easily-installable catalogue of free and open source apps for Android. With F-Droid, it's easy to browse and install apps on your device, and keep track of updates. You can also browse the repository with a web browser, and download the app directly from there, if you can’t or don’t want to run the F-Droid client on your device.
All applications in the default repository must be Free and Open Source software – for example, released under a GPL or Apache license. Every effort is made to verify that this is actually the case, both by visual inspection of the source, and by building the application from the published source.
Software that reports user activity without permission (e.g. via Google Analytics) or tracks user behaviour (e.g. most advertising platforms) is specifically excluded from FDroid’s own repository, as is software with the primary purpose of interacting with a non-Free network service. You are, of course, free to set up your own repository for this kind of software – the server source is available, and the client will allow addition or removal of repositories as you see fit.
F-Droid originated as a fork of Aptoide. F-Droid can be installed from its website or from within Aptoide, but it is not available for download in Google Market.
Uptodown is an international download site for mobile apps and desktop software. It was created on December 20, 2002, and is based in Málaga, Spain.
Its catalogue currently includes more than 100,000 applications for the main computer operating systems, divided into themed categories and stored on Uptodown’s own servers. Each application has its own information page written by the Uptodown editorial team and complemented with user opinions.
Its webpage is available in 15 languages, and provides secure programs thanks to VirusTotal, which supplies reports on all files based on the results of more than 50 antiviruses. Besides the software catalogue, Uptodown has a blog for news and tutorials related to the world of software, as well as its own official native app for Android.
The Amazon Appstore is a place to purchase and download apps for your Android device. You can get a paid app for free every day, and see app recommendations based on your past Amazon purchases. You can also test apps on a simulated Android phone using a feature called “Test Drive.” Access the Appstore from your computer's web browser, or directly from your phone or tablet.
To purchase apps from the Amazon Appstore and install them to your Android device, you will need to have the Amazon Appstore app installed on your device. To get this, follow these instructions: http://goo.gl/p9KKI To purchase paid apps, you will need to have an Amazon account set up with either your credit card or bank information. All paid app purchases will be automatically charged to the card associated with your account, and you will receive a receipt for each app purchase.
Amazon Appstore is only available for customers in the U.S. Due to restrictions regarding third-party apps, most AT&T phones do not support the Amazon Appstore.
Google Play (formerly the Android Market) is an online store by Google for Android devices. Browse and search for apps, books, and movie rentals from your web browser or Android device.