There is an alternative to paying for good music that does not involve Pirate bay and their ilk - iTunes Radio works great in iTunes.
You can choose the music genere/artist/titles you like and itunes will string together a playlist for you. You can 'fine tune' the channel by telling the radio your preferences for the song currently played.
Unlike Spotify, you can play it both on your macs AND iOS devices without subscription. Any stations you create on the desktop will be available on the iOS device and vice versa. However, unlike Spotify, you are not able to specify exactly what song you want to listen to.
Just watch your data usage if you are using 3G or LTE.