prepaid

动词 prepay:

1. pay for something before receiving it
   同义词：prepay

形容词 prepaid:

1. used especially of mail; paid in advance
   同义词：postpaid

1. I use a prepaid envelope.
   我用了一个邮资已付的信封。
2. The telegram was sent reply prepaid.
   电报已发出并已预付复电费用。