I never sell parts because I don't want to jack with idiots like that. On the other hand, I have given away a lot of stuff over the years, and, once I gave some guy in Florida an up pipe with an ATR bov mounted on it. I paid the postage as well.
He bitched about the way I packed it and sent it priority mail because it might have been damaged even tho it was not.
I still stick pins in his doll when I am in the mood.