Does anyone have a free iTunes song code I could use for a school presentation ?

In my high school class we have been asked to make a presentation on our iPads on iMovie. Does anyone have a free code or know a way to get a free code for a free song. I just need one song which is supposed to represent the title of the presentation. The title of my presentation has to do with life and I chose Coldplay - Viva La Vida which in Spanish means to live life. I would truly appreciate if anyone could get me a free song code for iTunes.