The cost of medicinal cannabis is set to tumble after Associate Health Minister Peter Dunne approved a Canadian pain relief product.

It is estimated the marijuana-based tincture called Tilray will cost at least 50 per cent less than the existing legal product Sativex, a UK mouth spray made by GW Pharma.

Multiple sclerosis sufferer, Dr Huhana Hickey, who applied to use Tilray, said: "I'm so relieved. It's going to save me $700 a month."

The AUT academic says she has spent $9000 on prescriptions since she started taking medicinal cannabis in February. Hickey says the results have been remarkable.

"I'm living my life again. I'm back to work, I am fully-functioning"

The marijuana grow-light story sits at the intersection of semiconductor cost curves, cutting-edge indoor botany, utility efficiency incentives, outlaw pot growers, and the slow societal acceptance of a newly legal intoxicant.

And it's a very big business.

Medical cannabis sellers are in Vancouver this week hoping to catch a glimpse of what their future may hold in light of the looming federal legalization of recreational marijuana.

Workshops at the International Cannabis Business Conference that began Thursday and continue Friday include titles like "Safeguarding medical marijuana as legalization unfolds" and "The future of dispensaries in Canada."

The medical marijuana industry has flourished in the past decade, dominated by federally illegal but municipally sanctioned dispensaries. These small businesses operate despite a federal dispensary system led by large-scale producers. 

Renowned billionaire and tech entrepreneur Richard Branson told a room full of cannabis advocates he was simply in the mood to "take a spliff or two," and much of the world is ready to legally take some tokes, too.

"Why not?" the Virgin Group founder asked a crowd of about 1,000 people Saturday during the second annual New West Summit conference, "The Future of Cannabis, Now," in downtown San Francisco.

Speaking via Skype, Branson, an unapologetic cannabis supporter, said he's spent the past five years serving on the Global Commission on Drug Policy along with former United Nations General Secretary Kofi Annan and 15 former world leaders calling not only for the controversial decriminalization of drugs, but also for its legalization worldwide.

No matter who wins on Election Day, cannabis will have a big day at the ballot box.

Five states — Arizona, California, Maine, Massachusetts and Nevada — have initiatives to legalize marijuana for adult recreational use. Four states — Arkansas, Florida, Montana and North Dakota — have proposed legalizing marijuana for medical purposes. All of the recreational use initiatives are currently ahead in the polls.

The Nov. 8 election can't come quickly enough for some people -- especially for supporters of California's recreational marijuana legalization initiative, Prop 64.

Diners smoke marijuana as they eat dishes prepared by chefs in Lyons, Colorado. Brennan Linsley/AP

Science tells us that the munchies — a phenomenon in which marijuana users overeat while high — is a real thing. Pizza never tasted so good after a joint.

Now a school in Denver, Colorado, aims to add a touch of class to this stoner tradition.

The New West Summit at the Hyatt hotel in downtown San Francisco looked similar to other business conferences held there throughout the year. Men and women in business suits hurried around, people huddled in corners talking shop, and unembellished booths showed off varied graphs and charts.

But every once in a while, conference goers got hit with a strong waft of marijuana.

That's because this summit was all about weed. At their booths, companies displayed glass urns filled with buds, cannabis-laced chocolate bars and different kinds of vape pens and bongs. Yet among the firms touting this typical pot paraphernalia, there were other kinds of businesses dealing in marijuana: tech startups.

The North American Marijuana Index has gained 105% over the past three months, buoyed by expectations that California and several other states could vote to legalize recreational weed this November.

The North American Marijuana Index closed at $125.53 on Friday, down 5.6%. The index finished higher for the week and has tripled since the beginning of the year.

Top gainers on Friday included General Cannabis Corp (CANN), Grow Condos Inc. (GRWC) and MassRoots Inc. (MSRT).

The big day for Californians is less than one month away. On Nov. 8, millions of registered voters will be headed to the polls to decide whether or not Proposition 64, which would legalize recreational marijuana within the state and impose a 15% tax at the retail level on consumers, will pass or fail.