Found this deal through HUKD which says that this will work without a VPN. I haven't tried yet but it seems to work from what I read.
Price is 599 pesos which works out to be about A$29.59.
Maybe those that have bought a pass through overseas Microsoft stores can share some info on whether something like this has worked for them in the past.
Mods - if not suitable, please remove.
I think you can change your console region to Argentina, buy the subscription and then back to Australia. Thanks OP!