edit: $31.98 @ My Chemist / Chemist Warehouse - http://www.ozbargain.com.au/node/97776 not as cheap $/cap as http://www.ozbargain.com.au/node/91345 but still a good alternative to Ethical Nutrients …
cheapest usually $39.99 also Ostelin Vitamin D Liquid 50ml is $12.99 https://www.chemistwarehouse.com.au/product.asp?id=64041 (each 0.5ml contains vitamin d3 1000iu)