I agree with Em - youtube-dl is the way to go and avoids the trouble of ads, apps and complicated tricks.
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I don't use it for music, but it's is pretty simple to use even for beginners, but quite powerful once you get a grasp of the advanced commands. Ex. if there is someone's playlist that you like, you can use:
youtube-dl --extract-audio --audio-format mp3 --playlist-items 1,4,5,7,10,12,14,16-20,22,24 PlayListID
(where PlayListID is the portion of numbers and letter after "List=" in the url of the playlist)
They'll all auto-download into the same folder. And if you listen to different genres, there's even a way to adjust the command so certain downloads would go into separate folders, but I'm not that keen with it yet