Digital music is available in many forms. You can buy digital albums and tracks form music stores like iTunes or you can subscribe to services that allow you to download all the music you want and keep it as long as you pay the monthly fee.
Slacker is yet another alternative where you choose the tracks you want to listen to and create your own streaming radio station customized to your tastes. Slacker announced a new service called Radio Plus. Radio Plus costs $3.99 per month and offers features not previously available on Slacker.