LMMS is an open source digital audio workstation designed primarily for song and beat creation. It comes with a clean interface, an impressive library of samples and synthesizers, and several helpful demo tracks. It is available for Windows, Linux, and Mac.LMMS Website
LMMS is a mixed bag of making some tasks very simple, and making some unintuitive or downright difficult. Overall, the UI feels like it is more a hindrance than a benefit, though this may vary from user to user, and for different use cases. As free software, and one of the few DAWs built primarily for Linux, it is certainly worth a try.