One of the earlier quotes that comes from a letter that Chris sent to his sister is very important in pointing out the kind of values that Chris had and developed in opposition to his parents and their offer to help him out financially. In response to being offered a new car, note what he says:
I'm going to have to be real careful not to accept any gifts from them in the future because they will think they have bought my respect.
This of course is crucial in the way that it presents Chris's tough independent spirit and the way that he looks down on financial wealth and money. Again, this is supported from a card he wrote to Wayne Westerburg in Chapter Four:
Tramping is too easy with all this money. My days were more exciting when I was penniless and had to forage around for my next meal.
We see the true spirit of Chris McCandless in this quote and the way that he loved nothing more than to be in the wilderness dependent on nothing more than his wits.
Lastly, I would pick the last message Chris sent to Jan Burres and Bob:
This is the last communication you shall receive from me. I now walk out to live amongst the wild.
Here we see Chris finally succeeding in achieving his goal of entering "the wild," and the way that it represented for him a definite end of an era in his life where he felt it was necessary to sever all communication and start fresh.