Pay packet

It does if you get paid by the month.

In the US, this term is unusual today. Without context, this might mean an envelope containing payment for work done by a person. This method of payment would typically be employed when the work lasts for only a short period, say, a couple of months, the person being paid one time only, at the end of the time period.

The term might also be used, figuratively, to mean the total compensat

Dear Anonymous, thank you very much for such a detailed explanation! I have to admit, I didn't really get its meaning with the first answer to my question. I found yours really helpful!
I've come it across a couple of times on an Australian web-site. So, it looks like it's in use there.
Thanks again!

It's also used in the UK. See the definitions here http://dictionary.cambridge.org/dictionary/english/pay-packet and here http://www.oxforddictionaries.com/definition/english/pay-packet

Anonymous, thanks again!
I had looked it up in the Cambridge dict. before posting a question here. It was still not clear to me - the amount was a monthly, yearly income? The amount was just about a salary or all kind of income a person might have?
Anyway, thank you for your help!!