Karl Subban knows the cost of being a hockey parent in Canada. The patriarch of one of Canada’s most successful hockey families – his boys P.K., Malcolm and Jordan have all been drafted by NHL teams – he and his wife paid $5,000 each in one year just to register them in minor hockey in the Greater Toronto Hockey League (GTHL). “And that’s not including equipment and what not,” Mr. Subban says. “It was very expensive. But you make sacrifices. That’s what we did.” It’s widely known that Canada’s national winter sport is expensive to play. But various factors have...