(4) tappets with adjuster screw and jam nut would be US$340.
Postage options to Sydney, Australia are:
Priority Mail International, Small Flat Rate Box (free), 6-10 days, online delivery confirmation, US$24.75
First Class Small Package, padded envelope (US$2), no delivery estimate given, no delivery confirmation, US$16.90
The online postage calculator is not displaying the insurance options, so I am not sure what to add for that, but it would be at cost like the postage. I have been shipping the tappets in padded parcel envelopes, and they seem to be arriving undamaged. I also place them in a zip-loc plastic bag to protect them from possible damp.