I know this has been discussed before, but I recently won a lot in an auction for 3 graded cards for $100 and the shipping charge was $14.
It seems like with insurance, packaging materials and priority shipping the actual cost should be no more than $10 by any calculation so the extra $4 is at least another 4% added to the buyer's premium.
It's the first time I've bid in with this auction house and for this reason it will probably be the last (unless I see something I really really need

).
I don't have any problem with paying actual cost, but I would hope that any "handling" charges would be included in the buyer's premium.
Sorry for my ranting.
-Alan