Polish Post Office provides a service solving this very problem: the sender can marked the parcel with ``recipient opens the parcel in presence of mailman before payment and can return it right away without payment if she so wishes'' option. This optional service is quite cheap, at about 10% of general shipment fee methinks. The other downside is that recipient have to pick the parcel, either at doorstep or at the post office; it cannot be left in the mailbox.

On polish market, `allegro.pl' -- rather than eBay -- is the dominant auction/garage sale platform, and it is somewhat common to request such option when ordering from sellers without reputation. There is some abuse of this system, but it seems low enough.