Australians are among the largest consumers of marijuana in the world, and estimates show that their expenditure on marijuana is approximately twice that on wine. In the present paper, the evolution of Australian marijuana prices over the last decade is analysed, and a decline in real terms by almost 40 per cent is shown. This decline is far above that experienced by most agricultural products. Why has this occurred and what are the implications? One possible reason is the adoption of hydroponic growing techniques that have enhanced productivity and lowered costs and prices. Another reason is that laws have become softer and penalties reduced. Patterns in prices are found that divide the country into three broad regions: (i) Sydney, where prices are highest; (ii) Melbourne and Canberra, which have somewhat lower prices; and (iii) everywhere else, where marijuana is cheapest. An exploratory analysis indicates the extent to which the price declines have stimulated marijuana consumption and inhibited the consumption of a substitute product, alcohol.