I keep all of my receipts when I buy things like computer components, other electronics, or pretty much anything that has a warranty or cost me more than $100. I have a file cabinet for all of that stuff.
I was just trying to protect this guy, I have a friend whose computer was stolen a few months back and found it on Craig's List. As such, any time I buy used electronics, I try to get some form of proof of ownership from the seller before I purchase.
There is a lot of negative criticism in this thread, and in my opinion it's pretty ugly. If you think that the seller is overcharging, there are better ways to say it than to blast the guy and laugh at him. Suggest better ways of selling it, like JDBNSN did. Calling someone retarded or laughing at him for a difference of opinion does not speak highly of yourself and only detracts from our community here.
Remember, we are here to help, share projects, learn, encourage and inspire each other. Not to get in petty internet flame wars.