Re international shipping, if you are doing bulk shipments to one country you should try to find an export agent to handle it for you.
From my experience, the USPS (post office) global priority is inexpensive but slow - they accumulate enough packages to fill a container then it gets shipped. You can't get USPS tracking outside of the country. International shipping via UPS is extremely expensive because all packages are expedited, but you do get the tracking and insurance.
I did meet someone who was exporting motorcycle parts. He shipped them to CA to a broker who put them in a container, taking what would have been several thousand dollars of UPS shipping down to a few hundred dollars.
Customs is another factor, each country has unique requirements and you can drive yourself crazy trying to keep up with them. Some countries limit package size, certain items are prohibited, embargos, the list goes on. The UPS web site has some good info on this that will apply no matter what shipper you use - http://www.ups.com/ga/CountryRegs?loc=en_US
Hope this helps a little