For clarity, currently there is a free version but this is not yet open source. They still say there will be an open source project after the mac version is finished and released.
Current #Lightworks roadmap: finish Linux alpha tests, then public beta, then stable. Then do same for OSX. Then launch open source project.
https://twitter.com/ESLightworks/status/268166856974688256
Things have always taken considerably longer than they say they will, and the source code release is, at the moment, 3 years later than first stated.