This response is written in reply to the above question posed on Musings by @kaponaki
I only know about state prisons in United States. Prisoners are allowed to listen to music if it is on the common television in the common areas. For a prisoner to listen to his own music in his cell, it's a matter of money. Prisoners must BUY their music and it is very expensive in relation to outside music services. For instance, they have to purchase a player through the prison commissary only. Then they have to purchase the music from an online service, again only through the prison system. The current cost is $35 for 20 songs that they can download to the player they have purchased. Again, it's all about money. Since prisoners have no money, it's up to their loved one to fund these commissary accounts to buy them these small concessions. And if the prison system made the money from these things and used that money to better their circumstances, that would be one thing. But all these services are contracted out and private companies are making all the profits. This is why prison reform is much needed.