Add Music to Video Free is a free iOS application that allows you to add music to any video. You can import any video from your device and add music from your library to that. Change the music volume for the final exported video. Save to camera roll or share to your favorite social network.
This version would add a watermark for the exported video, if you want to remove that just upgrade to the full version.
Requires iOS 7.0 or later. Compatible with iPhone, iPad, and iPod touch.