Give me a postal order, please.

请给我一张汇款单。

I need a postal order, please.

请给我一张汇票。

Yes. A postal order for 25p.

是的，来一张25便士的邮政汇单。

Can you cash this postal order for me?

你能替我兑现这张邮政汇票吗？

A postal order for 100 dollars, please.

要一张100美元的邮政汇票。