It doesn;t have to be a terribly big risk (obviously it will always be bigger than cash..)
1.) Agree to ship only to a registered address.
2.) Be absolutely clear, through paypal correspondence what the buyer is getting and include all model and serials numbers in your invoice. YOU BILL the buyer, they don't just blind send the money.
3.) Videotape yourself, making sure to show the serial and model you mentioned in your listing, boxing and mailing the package; the taping should be uncut. Better yet, have someone box it for you professionally and tape them doing it. I have done the latter, promising to only essentially tape hands, no faces, at a UPS store. YMMV finding someone willing to do this though. Usually this only costs an additional $10... worth it.
4.) All packages must be insured to cover the seller, so don't even consider not insuring it.
5.) Should they do a chargeback, paypal will ask you to present evidence of your legitimacy. That video should be more than enough.
All that said, you shouldn't have a hard time selling it locally for nearly what this person is offering, unless they are simply offering ridiculous amounts of money, in which case they are likely going to have you ship it to some unregistered address.