ADA sellers can get in trouble for selling outside of their ummm....country/range. The price is debateable, some people believe the prices could be much lower, especially when compared with American prices. Another aussie online retailer was selling it a year or two ago for a much lower price, but I believe they lost their right to sell it or something? Suppose it depends if your in it for the money or for the hobby.
thats more expensive than the prices ive seen online. If you want native shrimp have a look at www.aquagreen.com.au you want the caridina not the macrobrachium/cherax, its possible bettas will eat them.