Yup! CK is, was, and always will be 100% free, even when it's completed :)
That being said, I will be offering an open source version (non encrypted) for between $5 to $15 which will come with all the assets and code and a license which will allow you to do anything you like with it. Make mods, use the assets in other games, use the code as a template for your own game... whatever you like!