The new Creative Cloud pricing can make Photoshop and other Adobe products cheaper, but Australian customers still pay a hefty premium compared to those in the US even if they download the software. However, it turns out that with a little URL tinkering, you might be able pay US prices for an Australian copy. Update: Damn, looks like Adobe has fixed this.
Reddit user mrWLSN demonstrates in a series of screenshots how going through the US store but using an Australian ID results in an error. However, if you edit the URL to add /au/ after the .com, it seems you can then pay the US price via the Australian system. It's not clear if this would work if you want to buy a new copy, but it could be worth a try.
Adobe is one of the obvious targets of the upcoming government price inquiry. If it doesn't close this loophole, it might not be such a prime candidate. If you give it a try, tell us how it goes in the comments.
Update: Per the comments below, looks like this isn't working any more. Curses!