It's well known that Canada's single-payer health care system frequently results in delayed access for health care, since the "free" but still scarce medical resources get inefficiently rationed by non-price methods such as long waiting times. For example, the median wait time in Canada for a "free" MRI in 2009 was 9 weeks, but can be as long as 15.5 weeks in some provinces (source), compared to a wait of generally less than a week in the U.S.
Here's one description of the situation in Canada:
"It's like the old Soviet system. Everything is free, but nothing is readily available. Except that we're not talking about lining up for toilet paper in Russia in 1976, but queuing for surgery in Canada in 2006."
But now there's a growing black market in Canada that allows patients to make cash payments to get to the head of the line or get the experienced surgeon they want, according to the Montreal Gazette in this article, "Want Fast Care? Slip an MD Some Cash
"When their mother was diagnosed with pancreatic cancer, the twin sisters didn't hesitate for a moment: They chose the surgeon they wanted and slipped him $2,000 in cash to bump their mother to the top of the waiting list.