Open source: anyone can use, study and modify it, including businesses. Free: no cost, but the code is closed. Freemium: a lasting free plan with paid tiers for extra features. Source available: code is public but the license adds conditions.
FAQ
What is the best free alternative to FL Studio?
The most popular picks are LMMS, Waveform Free, GarageBand and Ardour. For making beats the FL Studio way: LMMS. For VST plugins and unlimited tracks: Waveform Free. On Mac or iPhone: GarageBand.