Amazon Prime is indeed adding music to the mix. On Thursday, after much speculation, the online retailer is launching a streaming service called Prime Music, at no additional cost for Prime members who pay $99 a year. Those members will automatically gain access to more than one million songs, including what Amazon says are tens of thousands of albums from top acts like Justin Timberlake, Pink, Bruno Mars, Blake Shelton, The Lumineers, Bruce Springsteen, and Madonna. Amazon Prime has come a long way for a subscription service that was initially all about two-day free shipping. Through the nine years of Amazon Prime’s existence, the company has added streaming movies and TV shows, and a Kindle lending library of more than 500,000 books. As part of the new no-cost music benefit, Prime members will be able to listen to hundreds of pre-programmed Prime Playlists that are artist-, genre-, mood- or activity-based.