First Recreational Marijuana Shops in Colorado

Denver (CNN) -- Colorado will begin allowing recreational marijuana sales on January 1 to anyone age 21 or over.

Residents will be able to buy marijuana like alcohol -- except the cannabis purchase is limited to an ounce, which is substantial enough to cost about $200 or more.

It's a big moment: Colorado will become the first state in the nation to open recreational pot stores and become the first place in the world where marijuana will be regulated from seed to sale. Pot, by the way, is the third most popular recreational drug in America, after alcohol and tobacco, according to the marijuana reform group NORML.

Voters wanted this. And the law is now in the Colorado constitution after 65% of voters said yes to legalizing recreational marijuana.

If you are 21 or older, you can buy up to an ounce at a licensed store, as long as you have a Colorado ID. People from outside Colorado can buy a quarter ounce. Only a handful of stores, however, are expected to open on January 1, and Denver will be home to many of them, according to the Denver Post and the weekly Denver Westword.

In fact, there are concerns that supplies will be sold out on the first day, with so few stores having passed the lengthy licensing process so far. About 160 retailers are still seeking licenses statewide.

Users can also share an ounce of cannabis with a friend as long as no money is exchanged. You won't be allowed to smoke pot in public and, in fact, can't even smoke in the pot shop or other establishments governed by the state's Clean Indoor Air Act.

That leaves the smoking to private properties, with the owner's permission. Communities and counties can still choose not to allow recreational marijuana stores in their local jurisdictions, and a good many towns have, such as Colorado Springs and Greeley. You can grow up to six plants in your home, but the pot patch must be enclosed and locked.