You'll have to pay excess postal charges on this letter.

这封你必须付超重邮资。

All letters must be stamped with the correct postage.

件都应该按所需邮资贴邮票。

An aerogramme is writing paper, envelope, and postage all-in-one.You can get aerogrammes at any post office.

航空就是、封和邮资全在的件，你可以在个邮局买到航空。

Price $14.90, postage included.

价格14.90美元，邮资包括在内。