Pandora Internet Radio
Pandora is the de facto "Internet radio" app for mobile devices; it customizes a music playlist, or station, based on your selected songs, artists, or genres. After you sign up for a Pandora account in the Pandora app, you can create up to 100 stations. The next time you log into Pandora, you can play a station you choose. You can also customize your settings such as giving the song you're listening to thumbs up or thumbs down; if the song receives the latter ranking, the song will be removed from your station playlist.
Price: Free