Firefox OS of course doesn't necessarily have "native" apps, but instead has gone for the webOS model of HTML5 apps instead. 7digital has optimized its service for Firefox, fully localized for Europe and North America, and released its app into the Firefox Marketplace. The service offers 25 million tracks, but there is no all-you-can-eat option. You have to purchase tracks or albums individually, and they will be stored in your "cloud locker". The good thing is that the service is DRM-free, so you can access your music on as many devices as you want.
It's still a long road to relevance for Firefox OS, but developer support always goes a long way to traveling that road.
source: The Next Web