Yeah I can get a price, there are 2 ways. EMS is the popular 'reasonably priced for the time it takes to arrive' air freight option, which I'm not sure if an 18x9 will fit in their maximum dimentions.... I was told 17x9 with just bubble wrap packaging would squeeze through. If EMS is out of the question, you'd have to go sea freight. Trouble with that is, you *will* get hit with GST and customs duty and port charges and bla blah blah (seriously it's mind numbing all the BS charges they have) but it's all dependent on your weight/size, so hopefully a set of wheels won't cost that much.
I've only ever done the 'containerless' sea freight once before for 2x wheels sets, 1x bodykit/mirrors/headlights/tail lights, 2x carbon bonnets, 2x carbon bootlids... so for that we paid in excess of $1,300, but it all weighed 185kg and took up over 3 m3 (cubed).