Gimp and Inkscape are both free as well. They available for most platforms I think. Windows, Mac and Linux for sure. You can find Gimp at
www.gimp.org and Inkscape at:
https://inkscape.org/release/inkscape-1.0.1/
These have a learning curve of course, but it's easy enough to find free tutorials. There are support forums on Reddit.
Regards,
Steve