Many US companies don't want to deal with overseas customers thru regular postal service due to inability to track shipments and lengthy reimburstments/insurance cases. Usually it's not even the USPS but service in the other country. So sellers would go for Fedex or UPS which tracks and doesn;t deal with other gov't agencies. But that will also cost you as you mentioned in your case $100 something.

Find a place that can ship thru the United States postal service insured. If merchant is not willing to do it for you, do it thru Ebay. Sellers on ebay (especially one who want to build they feedback) will go out of their way to help ya. I shipped 15 lbs packages to Taiwan for $40 insured.

Matt