Oh how familiar are the stories and experiences. I too watch packaging and postage to OZ. I find Jinny Beyer and a couple of other sites are really good at keeping postage prices to a minimum. I have frequently challenged a projected postage value before actually submitting the order. On most occassions the supplier was able to reduce the $$ value considerably.
I only purchase when the exchange rate is reasonable. It's amazing what the exchange rate can do to the final $ value.
However when all is said and done the US$ price of fabrics and notions are so much lower than we are urged to pay in OZ. I will continue to look at US web sites and when possible, buy from reputable US stores.