There has always been money in marijuana the only change is who the players are now, instead of running from the government we are paying them to protect us vs others paying them to harass us.
Now the money will be taxed, banked, borrowed and counted so there will be a lot more people getting tiny pieces of the money from weed. In reality it isn't going to get cheaper we will pay more simply because now we pay for the government structure from the money as well.
The positive side to legalization is it allows us to get along a little better, soon we'll have less needless jail sentences and less incarceration. The cost of fighting ourselves for the last 100 years has been insane.