I'm parting out my red racer, and a kid at the LBS has asked me for a "gruppo" price on the whole lot.
Without going into detail, the lot of parts would sell (after shipping, and as individual parts) for about $900 via e-Bay. I've verified this by looking at the individual parts in "completed listings" auctions.
If I knock off $50 for the shipping, about how much more discount should I offer for the convenience of not having to pay e-Bay fees, PayPal fees, and to ensure the continued good relationship with my LBS and its employees? I also get an immediate sale instead of having to wait until Spring when prices rise to "normal" levels again on e-Bay.
Of course, this may be all academic if the kid is wistfully hoping for a yard-sale price on the lot.