dankind wrote:If you don't need to have them tracked and/or insured, First Class U.S. Mail would be your least expensive option.
You can ship it certified (or maybe it's Registered??) which then allows you to track on the USPS website for an additional $12.00 or so (can't remember exact price) on top of whatever the postage cost is for First Class. Or maybe look into international express flat rate, you can probably use the document envelope. International Express comes with tracking, International Priority does not.
Check here: http://ircalc.usps.com/?country=10013