The rate is $2.10 ( Australian) from up to 50 grams via air mail from Australia to the US.
It depends on what you are sending. You can calculate postage, see the related source link below.
It takes 42 postage stamps
It depends where you want to send it from.
The number of stamps must equal the amount of postage. The postage depends on the weight and and form of transport.
The stamps have to add up to 45 cents.
one
Australia is one country that makes personalised stamps. Produced as pairs, one with the correct postage joined to one with your picture on it.
The number of stamps that you need to send a letter from Australia to London, will depend with the value of one stamp.
Just one.
umm 1000
Postage is based on weight, not distance.
One first class postage.