DENVER (CBS4)– January 1 was an exciting day for retail marijuana supporters but not everyone believes it’s the best move for Colorado.

Hundreds of customers lined up outside retail pot shops to ring in the nation’s first sales of recreational marijuana.

“We’re going to show what good can come of it and how to use it responsibly because it’s less dangerous than alcohol and tobacco,” said Denver resident Robbie Leach.

Others traveled from out of state to be among the first to legally buy marijuana.

Steve Dorgan drove 12 hours from North Dakota then spent several more hours in line to witness history in the making. He said his life has already changed.

“More freedom. More individual people can do what they want to do and not have to look over their shoulder,” said Dorgan.

Activists believe legalizing pot for adults will bring more jobs and tax dollars to Colorado. They also believe it’s a better alternative than the costly war on drugs.

“I’m glad we’re taking this out of the back alley and bringing to the light of day and I think we’re going to end up with a safer community because of it,” said Representative Jonathan Singer, a Democrat representing Longmont.

Not everyone supports the new law. Dr. Christian Thurstone from the University of Colorado Denver said marijuana, especially for adolescents, can lead to mental illness, a loss of intelligence and stunted social development.

“They’re going to want you to think it’s not addictive. They’re going to want you to think it’s healthy, natural, organic and a lot of things. My message to youth is don’t fall for that message,” said Thurstone.

Marijuana sales are expected to bring $70 million in tax revenue to Colorado.