for every 3 chip i add an ounce. I print labeles through paypal so i can get a tracking number too. Heres the ink i use(you need to sign in to your paypal to use it )
https://www.paypal.com/us/cgi-bin/webscr?cmd=_ship-now
For foreign postage, i can calculate postage here..
http://www.usps.com/tools/calculatepostage/welcome.htm?from=home_header&page=calculatepostage
I also attach a customs form for foreign packages,