Go to http://www.swfa.com for the best prices on the scope you are looking for. Once you have the price divide it by .9143 to give you an approximate conversion. Currency rates fluctuate daily but this will get you in a very close ball park.

i.e. Bushnell Banner Series 3-9x40 would be $76.51 AUD
BUSHNELL SPORTSMAN 3-9X40 Riflescope MULTI X Reticle $60.10 AUD
Tasco 3-9x40 Silver Antler rifle scope matte you can pick up for $38.22 AUD