human life is cheap? What if the drugs were cheap instead, "low cost low crime"?
That's why drugs should be very low cost, or preferably free. The lives of drug users aren't cheap, they are worthless. Whether it would appreciably lower the crime rate is debatable. The crimes not committed to get drugs would have to be offset by the crimes committed while users are on drugs and the crimes committed because there is no other source of funds to buy desirables.
In the beginning, it would probably mean a serious increase in criminal acticity, as users die off that would go down.
As far as saving money generally, it would not help the families of users who are deluded into providing medical care for them or rehabilitation services.
As HG has said, his father spent thousands of dollars on a worthless brother. That was money ill spent. Now if people stopped wasting their money like that, there might be a savings. As long as there are tax supported clinics and centers, the tax payers won't see any relief either. Whatever is spent on keeping users off the streets through the court system will be spent on their care and coddling. Again, though, as users die, these expenses will go down so it's more or less and investment in the future.