Ideally you would put a Pigouvian tax on heroin in order to make up for all the harm done to non-consumers resulting from heroin use. Most heroin users wouldn'

Ideally you would put a Pigouvian tax on heroin in order to make up for all the harm done to non-consumers resulting from heroin use. Most heroin users wouldn't be able to afford heroin if you put such a tax. The only problem with this solution is that most heroin users tend to resort to crime if they can't afford to pay for the drug, so this really isn't a solution.