GarageBand

GarageBand ships free on every Mac and iPad, and more hit songs than you'd expect started here. Rihanna's "Umbrella," Grimes' entire early catalog, T-Pain's demos, and Oasis tracks were all sketched in GarageBand before moving to Logic or Pro Tools. It's deliberately limited — which forces creativity instead of option paralysis. Apple Smart Instruments on iPad let complete beginners play complex chord progressions. It's the most important gateway drug in music production history.