There won't be any shortage of customers when recreational marijuana becomes legal in Canada next summer. Canadians consumed 697.5 metric tonnes of marijuana in 2015 alone, according to Statistics Canada. That's over 690 billion grams or, if you're not into the whole metric thing, it's also over 1.5 million pounds.

Or to give you an even better idea, 697.5 metric tonnes is roughly the same weight as five adult blue whales.

Yeah, these ones.

And all that weed didn't come cheap. Statistics Canada estimated the value of Canada's black market at $6.2 billion CAD ($4.8 billion USD). That's roughly the same size as Canada's $7 billion wine market and well over half of the $9.2 billion that Canadians spent on beer in 2016. In fact, that $6.2 billion is the exact amount that Canadians spend on coffee every year, so cannabis is already big business in Canada. 

But before the federal and provincial governments start drooling over potential tax revenues, they need to take a sober second look at the average cost of a gram on the black market. The average price ranged from $7.14 to $8.84 CAD, which is roughly two bucks cheaper than the $10 price tag that some jurisdictions are thinking of slapping on grams of marijuana. And charging more might end up bringing in less tax revenue by giving unhappy customers an incentive to take their business to the black market.

So if Prime Minister Justin Trudeau wants to achieve his goal of cutting the black market out of the marijuana industry, he needs to convince lawmakers across the country to put the interests of the consumer ahead of the taxman.