After watching the video, I have one suggestion for you in the future:

Always cut AWAY from yourself when using a knife.

UPDATE : I filed appeal, and paypal said "There was not enough evidence to overturn their decision" I called them and they refunded me 50 percent of the ammount.. which is great, but I'm negative on my paypal still. Oh well. I told them I'm not going to bring up the balance. Paypal wouldn't go to court over thirty-some dollars. (I hope) >.>

The guy was a jerk. You messed up saying it devalued it 50% I have had nothing but good relations with EBay and Pay Pal. They have removed unwarranted negative, refunded money to a complaining buyer and I got my stuff back and kept the buyers money, it does matter how you talk to them. I will say the video is 100% the best thing you coulda done. It's also good to get a conversation going with the buyer/seller and have them admit as much as possible or catch them in a lie.
You did okay I hope the douche who bought it is penalized. Did you check? Was this strickly Pay Pal or EBay? Ebay is who I'm referring too.
I have had WAY more problems here on the Realms than on EBay. On EBay if you have a customs number or DC number they will reimburse the buyer with their money not mine if they claim they didn't receive a package, if they believe them, I'm fine. Here on the Realms DC number/Custom number or not you are responsible until the package arrives. I still have negative feedback because some guy claims he never recieved a package I had a receipt and customs form for.

Paypal has put my account into collections because I refuse to pay the 30 they helped a guy rip me off with... Question - could this be called mail fraud?

Hah, thanks. I was so mad when I made the video.

With charges against the guy or PayPal? I'll assume you mean the guy, and its possible.

Yeah, I meant the guy. I told paypal that if I filed Mail fraud against the guy I could do something to paypal. Assisting a felony.

I would seriously doubt that. I am fairly certain that PayPal has some pretty clear language in their policies to prevent their liability in anything wherein you would go after someone else.
Seriously. Doubt. That.

Honestly your best bet is to pay up. You are most likely not going to get a federal prosecutor to file charges for mail fraud and surely will not get a county attorney or local law enforcement agency to touch this. You will spend more money fighting this than what it costs to pay up. While doing this your credit will get worse and worse. Pay paypal and re-sell the fig. If you think the fig is devalued by %50 for the damaged card I will buy it from you right now at %55. I am pretty sure I could still turn a profit on it.

You may argue that it's the principal that matters and not the money. Years down the road when you get loans that have interest rates 5%-10% points higher than what you would have got because of bad credit, you will wish you had thought differently.

I knew I had a wierd feeling about this thread. I can't imagine anything stupider than taking a credit hit over a few bucks on paypal. But then again the OP disregarded all the giant red warning flags about not making private deals through ebay messages, so how surprising is it really?