Well, it was completely free in the past 7 years while it was in beta stage of the development.
And it it still completely free now for creating and editing of small layouts (up to 100 tracks/objects).
But if you want to use the new SCARM v. 1.0 for larger layouts, be so good and pay the license fee - $30 is less than single new Lionel turnout.
If you donated or already has a license for MTS PE, you will get a free license key for the new version of SCARM. But you didn't, right?

Mixy