Thanks for the responses, guys, they were enlightening.
I neglected to provide some more explanation or a link. Spotify is a service, player, website, and company, that provide streaming music for free, legally. There's some public domain music but mostly what's there, and what's the appeal, is commercial (copyrighted non-free) music. The catch is that there are ads every few songs, unless you pay for the premium version, and I guess the other catch is that while there's a legal agreement and it pays the artists it's not that much. Also not every song or album (or artist or group for that matter) is available, but there's a pretty wide selection and more content is added all the time-- including a lot of video game music and music based on it. Recently I've started getting recommendations for Halo soundtracks because I listened to music based on game music, which reminded me to ask this. It's been available in the US for around three years and Europe for about several years longer; the link above should tell you if it's available in your country or not.