I think it's the respnsibility of the seller to state all fixed charges. There have been numerous times when I spotted an aucion minutes before it ended. There was, obviously, no time to inquire about such charges.

I would think that if shipping (and handling) charges are not posted, then no profit should be realized from this aspect of the transaction i.e., shipping charges should be actual cost. If you feel charges are excessive, then provide a prepaid mailer.