reply-paid
/rɪˌplaɪˈpeɪd/adjective
1- (of an envelope or card) for which the addressee will pay the postage（信封或明信片）由收件人付费的。
1.1
- historical (of a telegram) with the cost of a reply prepaid by the sender〈史〉（电报）预付回报费的, 已付回报费的。