The couriers all charge about the same. It used to be that Airborne was a little cheaper, but now they are DHL too they may be in the pricing carte..sorry, free open market.

Your other option is USPS air or sea. Sea slow, air quick. Air not massively cheaper than FedUPS. And insurance / tracking etc not as good. And a number of vendors won't offer USPS because of this. To answer your actual question: the cheapest way by far is USPS sea. If it is critical / valuable / desirable then prepare to dig deep and call 1-800-courierofyourchoice.

Oddly, gravity must be heavier in the US, because the same package going west to the US would be less than $170.

Regards

Mark