General ⇒ cost for using latex

[morgan26]

Hi !

I've been trying to find out if there are any costs / royalties that could apply to the use of latex in a proprietary program (on the fly generation of pdf based on latex).
So far, I couldn't find any good answer.. Having looked at the latex license (http://latex-project.org/lppl/) there doesn't appear to be any restricting clause. Am I mistaken ?

Thanks for helping me out !

Morgan