I'll leave out the gory details for now.
Here's what it comes down to: after I had received payment for my item and promptly shipped it, one hour later the seller files a "not as described claim", having suddenly realized that the listing title and the description and the note I included with the invoice describes something other than what he thought he was bidding on. >_<
I told him I would refund the purchase price (about ten bucks) after he did a return-to-sender on the package. I have no intention of refunding the shipping fee (also about ten bucks). At least the package is tracked.
Paypal isn't actually going to side with the buyer in this case, is it?