With the youtube to mp3 free download app you can download all of the Rihanna songs you want for free and it is totally legal. In order to legally download music from YouTube to your computer the music files must be for your own personal use and not shared online or locally for commercial gain. There are many different YouTube to mp3 free download apps to choose from so it would be in your best interest to test each of these applications on your home computer and get a feel for them before you make any decisions on which one you truly like the most.