International Stamps  
Send it overseas with stamps.
You can use stamps for most of your international postage needs.

Mailing overseas is easy. Once you know how much postage you need, you may use First-Class Stamps and Precancelled Stamps for international mail the same way you use them for domestic mail.

Note: Remember, airmail stamps may not be used on anything other than airmail items.
 
  International Rate Calculator
Find out the cost to send it overseas.
Go to International Rate Calculator

Nondenominated Stamps also may be used for overseas postage (except for those with uniquely domestic markings like First-class Presorted Mail, Bulk Rate, Presorted Standard Mail, or Nonprofit Organization).

Just be sure that in all cases the stamp value matches the current rate for international mailing.