So, I have no idea where this topic went. About your original question:
I say roll with the idea anyway. Regardless of whether or not there are holes in the argument, you can definitely write more than three measly paragraphs about all the interesting concepts and viewpoints that have been offered in this thread.
And I think that's probably the greatest reason to roll with the idea: it's novel and creative and interesting. I'll bet you anything a lot of your classmates are gonna go the easy and boring route and bring in a physically free item and talk about all the physical money that was spent to make it free, but imagine you roll up and start going off on an existential discussion concerning reality. To be honest, I'm impressed just by the fact that you thought that outside the box, and I'm sure your teacher would be as well (unless they're some kinda stick-in-the-mud who doesn't appreciate creativity or interesting ideas, or are one of those sticklers that has to grade everything line by line from a rubric or something).
Heck, go above and beyond with it. Write about everything discussed here. Talk about the merits of the idea of death as free-but-not-really-free and the numerous viewpoints you've gotten from talking to other people about it. I don't know what grade you're in, but this is easily college-level paper interesting.