Just four years ago, recreational marijuana (the kind you can smoke without a doctor's note) wasn't legal anywhere in the U.S. Now, voters have reversed the rules in four states and D.C.
Sales of legal pot grew to $1.2 billion in 2015, more than tripling sales from the year before, according to an industry report from Arcview. And that doesn't include the $4.5 billion brought in from medical marijuana sales.
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But rules are still hazy about where you can buy pot and who can smoke. It gets more complicated for those who want to sell it.
Here's what you need to know.
1. Anyone over 21 can buy marijuana in Colorado, Washington and Oregon.
It's been legal to buy pot in Colorado and Washington since 2014, and in Oregon since last October.
2. You can smoke it legally in Alaska and Washington D.C., as long as you're older than 21.
But it won't be legal to buy it in those states until lawmakers hammer out the details. Alaska is currently accepting license applications from future legal marijuana growers.
3. Medical marijuana is legal in 24 states, and D.C.
4. You can still be fired for smoking marijuana.
Even if you show up for work stone cold sober, you can be fired for flunking a drug test in most states.
5. The government owns and operates one pot store.
The city of North Bonneville in Washington opened the Cannabis Corner in early 2015. Profits go to special city projects, like upgrading the local playground.
6. There's still a black market for pot, even where it's legal.
That's because it's cheaper. Pot sold legally in stores is taxed heavily. If you're buying pot from a store in Colorado, there will be about a 28% tax. In Washington, it's 37%, and in Oregon it ranges between 17% and 20% depending on what city and county you're in.
7. Banking is still a huge problem for pot shops.
Pot remains illegal on the federal level. That means many shops can't get bank accounts, since banks are regulated by the feds. Retailers have to pay employees and taxes in cash, which makes the business dangerous. But legislation has been proposed to make banking easier for medical marijuana sellers.
