Farscape: The Definitive Collection [Blu-Ray] AUD $75 @ Amazon UK
The DVD version of this boxset was discounted recently, but now it's the Blu-ray version's turn. This seems to be the lowest price ever for this boxset, with a £23 discount compared to the pricing a few days ago, plus the Blu-ray boxset isn't even available in Australia as far as I know (ironic, given the nature of the series). Reviews say the video quality is only average, so take that into account (the DVD version is only $16 cheaper though).
The price is £57.99 minus VAT (removed at the last page of the checkout process), which becomes £48.33, which is around AUD $75. Free shipping to Australia, as usual.
And yes, it will work in Australian Blu-ray players, as both the UK and Australia share the same Blu-ray region.