Look...
The Guy either hated SHIII and gave it away.
Or he liked it, in which case he would not have gone for weeks without it.
That loan story, you can try it on your parents (wasnt me!), your teacher (dog ate my homework!), or on your ex (wasnt nothing!we were just hugging!).
all you need to do is ask google where to buy a copy, Hm?
Asking on a forum where to get a copy is kind of weird, as you might have realized. Smells like you are asking us to provide a link where you do not have to pay for the game. To put it that way.
I mean... you also asked for a video of the ending without being willing to put forth the time and effort to get there. Cheating...? Pirating...?
smells fishy, just saying.
...always a bad idea.
edit:
i forgot this link - it will get you what you need!
http://www.subsim.com/store.html