I tried getting costs to airfreight a pin a few years ago befor i actually sea-freighted in a few machines from the USA.
The cost to airfreight was HUGE. If u had a friend in the USA who could do all the hardwork for you, then it might be worth a relook if you could get a half bin on a standby rate. (Aluminium square small containers are loaded onto a aircraft and called bins in the industry, also, a standby rate is where the aircraft will leave not 100percent full so the airline will sell the unused space for apx half to a quarter of the price to a freight forwarder).
Getting something on a aircraft at stanndby rates is the only affordable way u could ever do it, but as Mike(Homepin) has pointed out, why bother, cause every size n shape of pinball machine u could ever ask for is for sale in Australia at great prices.
Seafreight is really the only way, and its still ALOT OF WORK & PRECISE PAPERWORK. Shop locally and save at least $1,000 to $1500 on unneeded import costs.