Priceofweed.com allows consumers to anonymously enter how much they pay for an ounce of marijuana in a given state, locations where recreational weed is legal is (as expected) where an ounce of high quality Mary Jane is least expensive. Today, Forbes has ranked the 50 states of the U.S. by the cost of weed. Oregon is currently the state with the cheapest marijuana, while North Dakota then leads the country when it come to the highest priced.