邮券 meaning in English

reply coupon

I am enclosing an irc / mint stamps of your country which i hope will towards your postage costs
随信寄上一枚国际回邮券/贵国的新邮票，我希望会用于支付回信邮资。
A coupon costs $ 14 and can be exchanged for international postage stamps for an unregistered air mail letter not weighing over 20g
回邮券售价为14元，可换作投寄一重量不超过20克的非挂号空邮信件所需的国际邮资。
These coupons are exchangable at post offices overseas for postage stamps and enable the sender of an international letter to prepay the reply
这些回邮券可于各海外邮政局兑换邮票，让邮寄信件往海外的寄件人能预付回邮费用。