Authors on GraphicRiver spend weeks coding these actions to ensure they handle skin tones, landscapes, and complex backgrounds correctly. Downloading their work for free undermines their ability to update the tools. Furthermore, if you use these assets for commercial client work without a license, you open yourself up to copyright strikes.
Whether you decide to purchase the legitimate license or try to work with a shared file, the result depends heavily on input. The action is only as good as the setup.
of premium actions (unless the author specifically runs a promotion). Any site claiming to offer "free GraphicRiver downloads" is likely pirating the files.