I looked to buy a number of them a few years back.
White PVC wood look blinds were what the designers were all buying - they were cheaper than timber and looked like the ducks guts.
Buying off the rack at Spotlight was quite cheap but if you wanted non standard sizes then the price went up dramatically. I guess Australian labour prices vs Chinese Labour was the key factor there.
But today you'd think that ordering online from China might be quite viable. I have bought wholesale direct from China (not blinds) and found the costs and ease to be much better than I had expected.