The $50 is the basic cost of the book, with shipping, in the US. Folks outside the US pay the total in the shipping area below so if you're in Australia you need to pay $80USD. I've switched prices to the Fedex-from-the-warehouse price because I'm too swamped to ship through the post office by hand. Shipping is -awful- and I'm sorry.
If you contact me directly Friday or later I can offer you a cheaper postal rate. It'll be $68-70. It's possible that I'll be sold out of books by then but unlikely.
The DTRPG option to Australia should cost $40-45USD but it does not have the foil and fanciness. Also, it'll never sell out.