Spotify to MP3

Hey everyone :) Someone might help me with my question? I' looking for a legal way to capture some of my spotify playlists and transfer them on my old mp3 player. (BC apps don't work on my mp3 :( ) I already did a little research but there are so many different tools and I can not decicide which is the best one (and of course they all say they're the best :D )… So any recommondation? I would be very thankful!