How to download free music onto an iphone?

Thank you to those who answer

I usually use an app called Xiami, it has newest music all over the world.
But it only afford chinese.

Install an addon to your browser that enables you download videos from youtube this works best with mozilla a quick google search will do the trick search for 'youtube downloader' this will add a download button to all youtube pages once you've downloaded your favourite music use a convertor like flv convertor (which can also be easilly gotten from net)to convert the videos to mp3 format you can then use itunes or similar apps like itools to send music to your device. Hope this helps!