How an i download songs for free on iPhone 4S?

I heard youtube mp3 rocket but it dosent work.

Most people prefer to stream music to their devices but if you still want to download it directly you use one of the many music downloading apps…

https://itunes.apple.com/...01678?mt=8

https://itunes.apple.com/...45719?mt=8

https://itunes.apple.com/...24243?mt=8

You can use an app called GTunes music. Or you just download the music from a site like http://kickass.to/ to your computer and transfere it to the iphone using a usb cabel