Charles' CD player is dying, so he's thinking of getting an MP3 player. Leo says that physical media is fading away and going digital is a good idea. He can take all the CDs he owns and "rip" them into an mp3 format. But it's likely that everything he owns and wants to listen to are available now using music streaming services like Spotify, Pandora, or Apple Music. They're around $10 a month or $15 for a family plan. And they offer offline downloading to listen as well. It's a good idea to try the free tier to see if that will work for him and then subscribe.
Or he can get an iPod Touch for $200 for 32GB, which is a lot of room. But if he already has a smartphone, he doesn't really need one.