I bought my Cabal Harvester from Amazon US during the 2017 Black Friday sales for $288.90 AUD ($217.95 + $70.95 shipping and handling to Australia)
Also, it seems Mattel is the official distributor for MegaBloks/MegaConstrux, but their international shipping costs are absolutely ridiculous. I investigated buying the Heavy Pike Patrol set through them when it first became available. They wanted nearly $80 shipping and handling for something that was 1/10th the size and weight of the Cabal Harvester!