Over the years, Amazon has added so many features to its Prime service that even subscribers may not be aware of everything the service offers. Amazon's Prime Instant Video may see a lot of use from members, but perhaps due to its smaller catalog or the fact that it only launched a year ago, Prime Music isn't mentioned that often.

It's also likely that Prime Music doesn't see many mentions because until now it has only been available in the U.S. That part has finally changed, because as of today, Prime Music is now available to Amazon Prime members in the U.K.

Prime Music's catalog features "over a million songs," which sounds like a lot until you look at Spotify, which features more than 30 million. Still, at 80 per year ($100 in the U.S.), Prime Music is cheaper than many of its competitors, and that's before you factor in all of Amazon Prime's other features.

"For many people 120 a year is a lot of money to spend on music", Amazon U.K. head of music Paul Firth told the BBC. He also pointed to another advantage that Amazon has: "Being the one place where you can make all those choices in the same place, you can buy CDs and vinyl, you can buy downloads or you can stream -- I think that's the best place to be right now."

Amazon Prime Music is available on the web, and apps allow customers to access it on iOS, Android, PC, Mac, and Amazon Fire devices. Older albums and artists are generally well represented on the service, but newer releases are often missing. If you're going with Prime Music as your streaming service of choice, these new releases can always be purchased from Amazon MP3.

While this marks the first time Prime Music is available outside of the U.S., Amazon hasn't mentioned whether it plans on bringing the service to other countries.