Australia has become very expensive to ship from lately, it sucks, my sales to USA used to be 90% nots its less than 10%, I used to be able to charge US$7 postage to the states, now it costs me on average $20 to send (plus an extra $6? if they decide I should pay US customs to check I aren't sending a bomb). As I sell cheap trash, its not worth buyers money unless they buy a number of things.
I have a poster for the TV version of THE SHINING someone wants, and i would give them it free, but they don't want to spend the $20 postage, so selling is hard.
Buying, I recently bought a bulk lot from Italy, some I posted here, I was quoted $50 postage, but when he posted it came out MUCH more, and was cheaper to send fed ex, so I had to pay an extra $120! (when I say "had to", he asked if I would mind as he was out of pocket, and I agreed to pay the extra). Needless to say it makes any profit margin for the ones I plan on selling a fair amount smaller.