As snowygst said: relax. Others have included some reasons for the disparity. Also, US prices exclude taxes, I don't know what the practice is in Australia but you probably include taxes when quoting prices. Cost of doing business in Australia is probably higher than in the US, so Epson and retailers require higher margins down under (just like here in Europe).
Even if the papers are manufactured in Asia, shipping costs for Epson are negligible (a few dollars) since they ship by sea in massive container ships where things are weighed by the ton. Shipping costs for you are very different, because you are getting a very heavy package couriered to you.
Finally, the fact that if you import it yourself the prices are the same as buying locally should give you a hint why prices are so different.
I understand perfectly there are often disparities in prices due to different taxes that may apply in diffrerent countries. Some countries may apply a customs duty in addition to a hefty GST of 17% or more, plus administration costs.
I recall once being amazed, when in the UK, a postman knocked on the door to ask for a payment of cutoms duty, GST and other charges, before handing over the DVD I'd ordered from Canada on the internet.
I'm thankful in Australia it is not considered worth the trouble and expense of collecting the relatively small amount of 10% GST, and sometimes maybe an additional small cutoms duty of 5%, when the goods plus freight, imported for personal use, amount to less than $1,000.
This makes internet shopping so worthwhile, but the 'bricks & mortar' retailers are not too happy about it and I believe there is pressure on the Government to reduce this limit. The limit used to be $500.
Having checked the tariff for imported photographic paper, it seems that there's either no customs duty or it's a minimal 5%. Refer to attached jpeg.
I could therefore understand why a roll of paper in Australia, which includes a 10% GST and maybe a 5% customs duty, might be 20% more expensive than the same product in America at a price which doesn't include any taxes.
I can understand that certain products in America may be cheaper because of the significantly larger market and issues of economy of scale, so I would expect another 20% or 30% increase in the Australian price, BUT 300% INCREASE!!
Bloody hell! There's something seriously wrong here.
After some searching, I did find a supplier in America who was prepared to ship a 24"x100ft roll of Premium Glossy to Australia. Their price was around $90 plus $223 freight (presumably by air) making the total price, delivered to my door, about the same as the Australian RRP.
However, one shouldn't have to pay the recommended retail price for any product if one is prepared to hunt for the best price. I've found a supplier in Australia who will sell that roll (the heavier 250gms paper) for the bargain price of $245, excluding freight which will probably add another $30 or so.
How does that compare with the best American price? $84.95 at B&H including free shipping in the USA, compared with $275 in Australia, including shipping.
Notice the slight difference?