If it is something I really want with excessive post & packing attached, I still bid and if I win, never ever admit to seeing their postage charges!
My standard letter to these types is always really friendly and innocently says "Could you please send it by second class (or if its in the USA Economy) mail, as I can't really afford to pay high postal charges"
They now have two choices:
a - Pay up you swine - we published our prices clearly, you pay them!
OR
b - If this guy drops out, we will have to re-auction this and might not get as good a price the second time. (That's why if you buy it cheaply, never argue about the postage)
It has never failed - honest. Every seller has then "reappraised" the situation and charged the base postage and very little, if anything, for the packing (this week I had £5.40 reduced to £2.50 with the message, I'll send it second class with "no-frills" packing)
Why don't they opt for Option a above? WEll, for one reason I never challenge their charges, I merely avoid the issue.
Go on, try it - remember softly, softly catchee monkey! Polite - perhaps over friendly letter, no mention of their postage charges (remember if they now say $37, you express genuine shock horror!) and a bit about you are not in a particular hurry (this gives them a "fig leaf" to hide behind if they drop their charges)
I always imply that I expect they normally ship first class, but I am quite willing to accept second class because I can't afford the best.
See being humble (and devious of course) can win you any battle!