You can re-use the textures in your own works. You can even create a new original work, using the textures as a reference, and pay nothing. The only thing you c

You can re-use the textures in your own works. You can even create a new original work, using the textures as a reference, and pay nothing. The only thing you can't do is use the reference textures directly in a new work without securing an additional license. I'm pretty sure that, by volume, most art is not sold in a commercial environment and its creators could use the book without concern.