The black market for weed in Colorado is still thriving, despite the existence of retail shops that sell it legally, according to exclusive interviews with growers, dealers and weed industry experts.

There are a number of reasons that people still call their dealers instead of visiting one of the state's 37 new Amsterdam-style dispensaries, which opened for business Jan. 1. Number one is the price: retail weed in Colorado generally sells for roughly $65, on average, depending on quality, according to marijuana.com.

Those high prices are mostly due to sky-high sales and excise taxes. Even though much of those taxes go to a good cause, the price on the black market is much lower for the same amount. Steven, a University of Colorado Boulder student who sells weed illegally, told The Huffington Post he only charges $30 an eighth for top-quality herb -- less than half the price it would cost at a recreational dispensary. (Steven's name has been changed to protect his identity.)

There are a handful of other reasons that might compel Colorado state residents to buy their pot on the black market. One reason, according to several sources, is that the quality of retail herb isn't always as good as the marijuana grown for medicinal purposes, which is often also sold illicitly.

"These recreational places aren't getting product that's up to par with the medicinal side, simply because they need to come up with a lot more product for the consumer," says Jacob, a legal caregiver who runs a grow operation of about 250 plants in an undisclosed location in Denver County and asked that his last name be excluded, citing concerns about the federal government. "The quality just isn't as good. There are a lot of big guerilla-type grow operations here. Some of them will cut the plant down after only 60 days, when in reality it needs 70 days to flower. There's so much demand that the plants get put on a schedule. But that's going to affect your high [if the plant is harvested prematurely]."

"The supply was always here, but now demand is going up," said Abdullah Saeed, a Vice journalist who has covered the marijuana industry extensively and who reported on the advent of legal weed from Denver last week. Saeed also noted that the selection of recreational weed at Colorado dispensaries is narrow because of laws limiting how much retail bud each store can have for sale at any given time. Lack of variety might drive discriminating smokers to find their weed elsewhere, Saeed said.

But the real money on the black market gets made out of state. "People here [in Colorado] can make about $1,000 off a $2,400 pound they bought from a legal grower by selling it [illegally] over the border in Nebraska," said Aaron, a Denver-based musician who has sold marijuana in the past. (Aaron's name has also been changed to protect his identity.) The amount of weed being trafficked out of Colorado has soared by over 300 percent in recent years, according to the U.S. Drug Enforcement Agency's El Paso Intelligence Center, which combats drug trafficking and other criminal activity in the Southwest. Colorado weed has shown up as far away as Florida and New York, according to The Denver Post.

But when the rest of Colorado's retail pot dispensaries open across the state, the black market may start to die off. "Only a small fraction of the businesses that are going to open are open right now, in only a fraction of the localities where they're expected to open," said Mason Tvert. "Not to mention that prices are going to drop dramatically. People are going to prefer to buy marijuana in a legal market. Not just because it's safer but because it's more convenient."