Yes it includes GST (10%) and that can be claimed back.
Also it's not uncommon to soft-launch apps in Australia before the US and the rest of the world as a large scale public test. (The market is considered by some to be very similar to the US.) So it might makes sense to roll a different line just for Australia. Maybe. Just throwing the idea out there :)
On the Australian app store it is $129.99. The Australian market is small enough that it's unlikely to be worth optimising for but I though I'd mention it all the same.
(For the curious AU $129.99 is about US $121 at the moment.)
Also it's not uncommon to soft-launch apps in Australia before the US and the rest of the world as a large scale public test. (The market is considered by some to be very similar to the US.) So it might makes sense to roll a different line just for Australia. Maybe. Just throwing the idea out there :)