It comes with a free version if you only want to download the video and audio files from YouTube and many other websites and if you want to be able to convert files and increase their quality you need to pay a monthly subscription and get the Pro version.
You can choose the MP3 format and download audio that you can then put on your MP3 player, iPad or any smartphone or tablet. Despite the name indicates that this tool is aimed at downloading YouTube videos, you can also use it to get the audio only.
