What is a good quote in the great gatsby, that I can use in an essay?

I am looking for a good quote that really captures the essence of this story.

Yes, this is part of a homework assignment, but I also need to give an explanation of what the quote is about, which I can do myself, so I am not cheating.

The reason I cannot come up with a quote is that altho I have read the book, I do not own it, and I am not able to get a copy.

If you still do not feel comfortable giving me a qoute could you at least direct me to a site that has the hole book on it, without me having to download or purchase it? (If there is such a thing)

Thank you.