Decriminalization is is worst than prohibition! You're still buying drugs from/supporting cartels, gangs, and terrorist organisations. Thier is still a risk of drugs being adulterated/poisoned. Legalizing something doesn't necessarily mean it's going to be taxed. However that would never happen because once legalized, drugs would be regulated ie tested for purity/potency by the government. That isn't free. Lastly, once legalized, all drugs including MJ, heroin, cocaine you cost pennies on the dollars of what you pay now. Joints would be sold in packs similar to cigarettes for around the same price- $10 including tax. 20 2.5gram joints for about $2 each isn't bad at all.