Free sexy films are everywhere my friend.
Did you know that sexually explicit movies are the number 2 activity that people online enjoy spending time on, the number 1 activity is now social networking (and that only became number 1 quite recently).
So really, if you are having trouble finding sex films to watch, then there are only two possible things going on here:
1) You do not know how to browse the internet
2) You are behind a firewall preventing you from accessing such sites.
I am not going to link you to any sites personally, but if you want free sexy films then I suggest you use a good search engine to help you find them.
If what you're looking for is not x-rated material, but rather a film with a a generally sexy theme then I suggest watching 'Cruel Intentions'.
It's one of the sexiest films I have ever seen.