Legal pot shops in Ontario should average more than $1.25 million in sales a month once they open, a Brock University business expert estimates.

"That's a very rough ballpark figure," said Michael Armstrong, an associate professor at the Goodman School of Business.

Among the variables Armstrong considered was Quebec's legal market, where stores average almost $900,000 a month in sales and charge $7.27 a gram including taxes.

Ontario's first 25 legal retail outlets are expected to charge higher prices than in Quebec. The lowest priced dried product available online on the Ontario Cannabis Store goes for $8.10 a gram including taxes.

Armstrong figures Ontario's legal stores will have to offer a discount product at some point to compete with the black market, where consumers can buy for as low as $5 a gram.

"At least it will exist for those people who want that lower price," he said.

Seasoned pot purchasers are also used to being able to select from a wide variety of products, Armstrong noted.

That especially holds true for Hamiltonians, who at one point could choose from as many as 80 illegal dispensaries in the city.

"What that suggests is that Hamilton has really strong demand for products," Armstrong said.

That could mean the city's two future legal outlets — one at Centre on Barton and the other on Cootes Drive in Dundas— might have more business than they can initially handle, he suggested.