The price is (almost always) right. (Brent Lewin/Bloomberg News)

Marijuana is really cheap relative to beer in most states—and really not in, well, only a few.

We used marijuana street prices from crowdsourcing site to estimate the price of a single marijuana joint (or roughly 0.4 grams of weed, because academia says so) in each state. We also took the listed price for a six-pack of beer from online alcohol retailer and applied state-specific beer taxes to approximate the cost of a 12 ounce bottle of Bud Light (or roughly one drink, because the government says so) in each state. What we found is that the relative affordability of each drug varies quite a bit depending on where you live.

Measuring the price of marijuana relative to beer might seem a bit arbitrary. After all, marijuana, however cheap, is still illegal in most of the country. But there's actually good reason to believe the comparison is not only telling, but a potentially significant indicator of future marijuana use in the U.S., especially among America's poor and young.

For those in Oklahoma, for instance, a joint is quite the bargain. Marijuana costs only $2.09 per joint in the state (the least expensive of anywhere in the U.S.), while a Bud Light sells for roughly $0.87 a 12 ounce bottle —meaning that price of a joint is the same as the price of 2.4 beers. In Kentucky, where a joint costs about $2.61, and a Bud Light costs roughly $0.90, the ratio is closer to 2.9; in Arkansas, where a joint costs $2.58 and a Bud Light $0.86, it's 2.99; and in Washington, where weed is $2.72 per joint and Bud Light $0.90 per bottle, it's 3.01.

For those in Nevada, however, marijuana isn't nearly as wallet-friendly. Marijuana costs more than $5.20 per joint in the state (the most in the country), while a beer runs for about $0.85—meaning a joint costs the same as more than six beers. In Wyoming, where a joint costs about $5.00 and a Bud Light costs just over $0.83, the ratio is roughly 5.99; In South Dakota, where a joint costs $5.02 and a Bud Light costs $0.86, it's 5.86; and in Vermont, where weed is $4.51 per joint and Bud Light $0.86 per bottle, it's 5.28.

"Cannabis is a remarkably cheap product to produce," UCLA's Mark Kleiman said in an interview. Kleiman is an expert on drug abuse and crime control policy. He says marijuana's low price makes it more accessible to minors and low-income users, who are more sensitive to price differences. "If you're a naive user [of pot] a half a joint should do you plenty. You're now stoned for three hours for two bucks. The Doritos cost more."

Widespread legalization of marijuana could cause the prices to fall even further. A 2002 study in Australia found that lower marijuana prices increased marijuana consumption and decreased alcohol consumption, with users substituting the former for the latter. Considering that many experts say that marijuana is a less harmful substance than alcohol on just about any measure, this may not be a bad thing.