Sure, here are some free online courses for script writing:

• Screenwriting from Alison. This course covers the basics of screenwriting, including character development, plot structure, and dialogue.
• Introduction to Screenwriting from Coursera. This course is offered by the University of California, Los Angeles, and it covers the fundamentals of screenwriting, such as the three-act structure and character arcs.
• The Fundamentals of Screenwriting from YouTube. This course is taught by screenwriter Michael Arndt, who has written films such as Little Miss Sunshine and Toy Story 3.
• Script Writing: Write a Pilot Episode for a TV or Web Series (Project-Centered Course) from Coursera. This course is offered by Michigan State University, and it teaches you how to write a pilot episode for a TV or web series.
• Creative Writing: The Craft of Plot from Wesleyan University. This course is offered by Wesleyan University, and it teaches you how to develop strong plots for your screenplays.

These are just a few of the many free online courses available for script writing. With a little research, you can find a course that fits your needs and interests.