Check out Free Music Archive for free and legal music downloads.
They have classical music, which is cool, because many free music sites don't.
Currently listening to Mendelssohn Violin Sonata Op. 4.
https://freemusicarchive.org/search?adv=1&quicksearch=mendelssohn&search-genre=Classical&&
This looks like a cool way to fill up my mp3 player! Yes, you do have to sign up, but use a fake name and a Duck Duck Go email mask.