A bargain hunter cruising a Vancouver garage sale has hit the jackpot after spending $100 on artworks that turned out to be by two iconic Canadian painters and are worth hundreds of thousands of dollars.

One of the paintings is by Frederick Varley, of Canada's Group of Seven, and the other is by Tom Thomson, who was not a member of the group but helped inspire it.

Paintings by the two men and those by other Group of Seven artists are often worth millions of dollars and hang in museums and galleries around the world

The buyer of the paintings, whose identity has not been made public, brought them in shopping bags to Maynards auction house in Vancouver in January, according to Kate Bellringer, director of Canadian and contemporary art at Maynards.

"I personally had not seen a Varley watercolour of this age, and the Thomson was extremely dirty and had been quite well handled," Bellringer said.

The find kicked off many months of work for Bellringer. The potentially more valuable Thomson had to be carefully cleaned and examined by experts across the country.

"It's believed he made about 400 sketches of this nature in his life, and to find one is extremely rare," Bellringer said.

Bellringer believes Thomson did the painting sitting in his canoe on a lake in Ontario’s Algonquin Provincial Park in 1915. It appears to depict a scene just after sunrise, with placid water in the foreground and hills, sky and wilderness beyond.

She's valuing the sketch-style painting at $150,000 to $250,000, but is likely to go for more.

"Normally, they would be probably closer to $600,000, but because it was found at a yard sale and it doesn't have the same provenance as many paintings do, we decided to keep the estimates conservative," Bellringer said.

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The Frederick Varley work was painted in England before he became a member of the Group of Seven. (CBC)

The Varley watercolour shows a view of Sheffield, England, painted before he came to Canada and became a member of the Group of Seven. It has been valued at under $10,000.

One of the first experts to see the Thomson painting was John O'Brian, a professor of art history at the University of British Columbia.

"My first thought in seeing the painting: that this was good, that this was right, that this was by Thomson," O’Brian said.

O’Brian said the brush strokes and colours looked right, but he advised the work be sent to Ontario, where they were examined by experts more familiar with Thomson's work.

There's always a concern about forgery, O’Brian said.

"Wherever there are large sums of money involved, and they are for Tom Thomson, and for Varley as well, then you have the possibility of forging," he said.

But the research done by Maynards suggests both paintings are authentic.

Buyers will do their own judging when they go for sale in mid-May.

With files from the CBC's Greg Rasmussen