Here is the list of my favorite free apps which is useful to handle our routine activities.
Dropbox - Its one of the best file sharing app for android.It is an excellent cloud service, which automatically syncs a folder of files amongst several computers like Mac, Windows, and Linux. It is one of the Top Best Android apps that lets you to access all your photos, documents, and other important files from any part of the world.
WhatsApp - It’s a messaging app that uses your 3G (or WiFi when available) to provide a cheaper alternative to SMS and MMS.
ResolutionTweet - It's a simple app that helps transform your bucket list or daily resolutions into action. It will provide the energy and motivation to change that Wish list into a Will list.
Instagram - It's a free, fun, and simple way to make and share gorgeous photos on your Android. Share your photos in a simple photo stream with friends to see - and follow your friends'
Dictionary - Perfect choice for referring words.
Maps - To find location without any difficulties.
Hope these apps will be useful for you all.