Now that pot is legal in Colorado and Washington, marijuana enthusiasts may think their drug of choice will get cheaper.

In theory, legalization allows growers to produce pot in bulk and spares them expenses associated with breaking the law.

"If production moves from basements and backyards to industrial farms and huge greenhouses ... we would expect the production cost to plummet," drug policy expert Beau Kilmer has told BI.

But the recent moves by Colorado and Washington to legalize pot won't necessarily herald the arrival of affordable marijuana, Slate's Matthew Yglesias reports.

Here's why pot might stay expensive, according to Yglesias:

  • Colorado and Washington are trying to make money off potheads, so it's likely the drug will be subject to the same kind of "sin tax" that has driven up the costs of cigarettes in New York.
  • Federal law still bars pot, so growers might be loath take advantage of the economy of scale and start huge marijuana farms the feds could easily spot.
  • They might also have trouble financing operations that are technically illegal under federal law.

The price of production could only go down if the pot is legal in the entire country, Yglesias says.

Read on to see whether the Supreme Court might make pot legal throughout the U.S.>