I'm no expert on the street price of heroin, but after talking to some people who are, I can tell you this: The illegal opiate at the center of the latest drug epidemic is very cheap. A couple of experts compared it to the price of a pack of cigarettes.

As a non-smoker, that sort of amazed me, so I decided to check. In many states, it is indeed true.

Ashley Kennedy, an addict currently in rehab, told me she could buy a bag of heroin in Baltimore for about $5. According to this survey conducted by The Awl, a pack of cigarettes costs $7.75 in Maryland. The Campaign for Tobacco Free Kids put the price of a pack at $6.45 in 2013. Either way, a single dose of heroin is less expensive than 20 smokes.

In southwestern Pennsylvania, where I spent a couple of days researching an onslaught of heroin overdoses, a single bag of heroin goes for about $8, said Rick Gluth, supervising detective on the Washington County drug task force. In the Keystone State, you'd do a little better if nicotine were your vice, but it's still pretty close: The Awl puts the price of a pack at $6.85, while the anti-smoking group says it's $6.25.

And in New York City, where heroin goes for about $10 a bag, according to a Drug Enforcement Administration official, a pack of cigarettes costs $12.85 or $10.29, depending on which of the two surveys you consult.

[One county, 69 minutes, eight overdoses]

Bags of heroin  (Photo by Marvin Joseph/The Washington Post)

It's important to note that The Awl gathers its data on the price of a pack of Marlboro Red via phone calls to convenience stores and gas stations in highly populated areas of each state, so we're not talking about a rigorous survey. The anti-smoking group uses an annual tobacco industry report that covers a wide range of brands and quality, and adjusts for certain factors.

And of course, a single dose of heroin might be more accurately compared with the price of a single cigarette, in which case the legal substance is still much cheaper. I'll leave that debate to all of you.

The big question is why you can buy heroin for less than a pack of cigarettes in some places.

For cigarettes, the price is largely about taxes. They are a reliable revenue source for governments at various levels (addicted people will often pay what they have to), are considered a method of preventing young people from taking up the habit and can push some smokers to quit. So some states have loaded heavy taxes on that little pack of cigarettes.

New York, which tops both price surveys, levies the largest excise tax on tobacco: $4.35 per pack, according to the Campaign for Tobacco Free Kids. It also slaps on a 40-cent sales tax and the $1.01 federal cigarette tax. A bindle (or bag or single dose) of heroin costs about $10 in New York, according to Joseph Moses, a special agent for the DEA who is familiar with street drug prices.

At the other end of the excise tax spectrum is Virginia, which adds just 30 cents a pack, plus a 26-cent sales tax and the federal tax. Not surprisingly, a pack of cigarettes in the tobacco-friendly state costs $5.25 according to The Awl and $5.14 according to the anti-smoking group.

[When life begins in rehab]

Heroin pricing is more complicated. For one thing, it varies by region, Moses said; it can cost more in Detroit than it does in New York, which is not what you'd expect given the relative economies of those two cities.

But in the last few years price has largely been determined by concerted action on the part of Mexican drug cartels, which previously controlled a smaller part of the U.S. heroin market, generally in the west, Moses said. Knowing that opiate pills such as Oxycontin have become too expensive on the street, the cartels did two things: they dramatically increased production and they developed networks to move it east of the Mississippi, he said.

Now most of the heroin on U.S. streets is from Mexico, Moses said, and despite the efforts of the DEA and other law enforcement agencies, there is plenty of it, which keeps the price down despite the seemingly insatiable demand. The DEA is seizing more and working better with those other agencies, Moses said, but so far that hasn't resulted in higher prices.

"The rise of the Mexican trafficking organizations and [their] push to heroin has kept the price where it's at," Moses said.

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