My currency is set to $Aus but when i submit a custom offer, it sets it to $US. How can I submit a custom offer in $Aus?
It’s not possible as far as I know. You can use a currency converter/search engine to get the equivalent price in USD and put that (rounded to a whole number since it doesn’t allow more precision than that).
You don’t charge in your currency. It just converts USD into your currency. This is all explained in the TOS.