Sigma BC 2006 MHR Cycle Computer @ Cell Bikes $122.95 delivered + cashback
Its quite hard to price these units in AUD as few places stock this particular model. What I could find is that they're selling for $129US at US retailers and you can pick one up off ebay for about $133AUD again from a US trader.
So this way, at least your supporting local and independant and your saving yourself in the region of 15% on the price not to mention that you get a bit of cashback as well. Its only at the price till Sunday apparently.
Full details can be seen on cell bikes site but I figure if your looking at this deal you probably already know what this unit is.