Salient Eye ( Android)
As far as free theft-deterrent and motion-notification systems go, Salient Eye has the lock on simplicity.
QuickPics Photo Manager ( iOS)
With easy to use tagging features, QuickPics gives you a better way to search your photo library, but only if you're willing to put in the work.
Humin ( iOS)
With better ways to search your contact lists, and tons more information for each contact, Humin is an excellent replacement for your iOS dialer.
Bookviser Reader ( Windows Phone)
Despite its sluggishness, the Bookviser Reader for Windows Phone is a great way to get free classic literature on your Windows Phone.
Lenka ( iOS)
If you're looking for a simple app for taking black-and-white shots using your iPhone's camera, Lenka is worth the price.
UpWord Notes ( iOS)
With gestures, theme customization, and plenty of other useful features, UpWord Notes is better than most competing title and a great replacement for Apple's Notes app.
ProCamera 7 ( iOS)
ProCamera 7 could potentially be one of the leading photography apps in the App Store, but unfortunately the bugs and issues in the current build make me recommend that you wait.
Google Drive ( iOS)
An elegant blend of Dropbox-like storage and mobile document editing, Google Drive is a must-have app, especially if you're a dedicated Google user.
Office Mobile ( Android)
Office Mobile is worth downloading if you're a current Office 365 subscriber, but with only basic editing features, this app should be free for all.
Fetch ( iOS)
Fetch is an entertaining adventure for both kids and adults alike, with colorful cartoon-like graphics, an extremely touchable interface full of little items to interact with, and challenging puzzles to solve as you explore a fantastical world.