DistroKid is a service created by Philip Kaplan that allows musicians to upload an unlimited amount of their music to stores such as iTunes, Spotify, Google Play, and Amazon and keep 100% of the royalties. Musicians can upload a single song to DistroKid for free, or pay $19.99 per year to upload an unlimited number of songs and albums. You can read more about the service and why Kaplan created it at his blog.
image via DistroKid