Washington became the second US state to allow the sale of marijuana for recreational use on Tuesday, although shortages and high prices are likely to accompany any euphoria.
Shops started to open on Tuesday, a day after 25 outlets were issued licenses under a heavily regulated and taxed system approved by voters in November 2012.
The nation, and the federal government, will be watching Washington's rollout as a broader trend of liberalization and pro-pot activism takes hold in the United States.. State regulators are still processing more than 300 license applications.
While Colorado has been raking in millions of dollars a month in tax since rolling out regulated retail sales in January, Washington has charted a glacial path to market.
Local media showed images of two people sitting on folding chairs with books and provisions almost a day before a "high noon" ribbon-cutting ceremony at Cannabis City, the only licensed retailer in Seattle, a city of some 630,000 residents.
The store's owner, James Lathrop, said he had 10 lbs (4.5 kgs) of pot delivered in the morning.
"We have plenty," he told CNN. "We're not going to run out today."
To the north, in Bellingham, Top Shelf Cannabis shop owner Tom Beckley was offering his first 50 to 100 customers special promotional pricing of $10 per gram, with prices rising to $12-$25 per gram depending on quality and type.
Depending on demand, Beckley said he might limit what he sells to each shopper to extend supplies.
Customers are legally allowed up to 1 ounce (28 grams) of marijuana before buying more. They also can buy up to 16 ounces (454 grams) of marijuana-infused product in solid form or up to 72 ounces (2 kg) of marijuana-infused product in liquid form.
Shortages may mean prices of $25 to $30 a gram on Tuesday, roughly twice the price at the state's weakly regulated medical marijuana dispensaries.
However, retailers such as Beckley said limiting the first wave of shoppers to buying a few grams will help deal with shortages, due in part to limited harvests by licensed growers, regulatory hurdles, and an applicant backlog.
And popular "edibles", such as hash brownies, are not expected to be available as no processor has been cleared to operate a cannabis kitchen.
Possession of marijuana is illegal under federal law, but the US Justice Department has said it will not intervene in states with "strong and effective regulatory and enforcement systems".
"This is a major shift in public policy, so it is not going to be perfect at first," pro-pot Marijuana Policy Project spokesman Mason Tvert said. "Like with alcohol, it will take some time to determine which regulations work and which do not."
(Editing by Louise Ireland and Susan Heavey)