Last summer, I had one of those "$400 emergencies," except in my case it could have been a four-figure emergency, and a potentially life-threatening one to boot. A primary care physician found a lump and sent me to a specialist, who sent me to a cancer specialist, who thought I might have a tumor. "You need an MRI," he told me. My immediate reaction wasn't just to worry about a malignancy. I also worried about the bills. Living in a big city with small children, my husband and I work hard to pay for the costs of daily life while also saving enough for retirement, college and the unknown. We're acutely aware that one of the biggest bombs that can get thrown into your budget these days is a medical bill. Even with a family health insurance plan for which we pay a steep premium each month, we know we're only partially protected. That's because, like , we have an even steeper annual deductible to cover before coverage kicks in, plus coinsurance and copays. So I set out to get a better deal. I found out what the MRI I needed would cost me at the hospital to which the cancer specialist referred me, and then I did some research, found cheaper alternatives and booked the scan at one of those instead. It may sound straightforward — what's more American than shopping around? — but almost no one does it, new research from the National Bureau of Economic Research finds: "Despite significant out-of-pocket cost exposure, patients often received care in high-priced locations when lower priced options were available. Fewer than 1 percent of individuals used a price transparency tool to search for the price of their services in advance of care."

Why comparing prices for health care matters

The hospital where I was sent to get my MRI could charge $2,000 or even $3,000 for the scan. I had no way to know. The average cost in the U.S. is $1,119, according to a 2014 survey by the International Federation of Health Plans, and everything in New York City is notoriously expensive. (By contrast, the scan costs only $130, on average, in Spain and $215 in Australia.) No one said anything to me about price when scheduling the scan. And yet, because of my cost-sharing responsibilities as the patient, I would be responsible for a significant amount of whatever the bill turned out to be. Indeed, the cost of health care is now Americans' top financial concern, Gallup reports. In 2016, 40 percent of Americans with employer-based coverage had something that qualified as a high-deductible health plan, according to the Centers for Disease Control and Prevention. That's up from 24 percent in 2011. That means millions of people are materially affected by the prices of scans like MRIs, and, assuming the trend continues, millions more will have to start caring very soon.

Fewer than 1 percent of individuals used a price transparency tool to search for the price of their services in advance of care. NBER report

But the problem is not just that health care is expensive in America. As Sarah Kliff reports for Vox, the prices are also secret. That makes it very difficult to shop around and try to find reasonable care at a price you can afford. Given that more than half of Americans, 57 percent, , one expensive scan could wipe them out. That's why impassioned activists like Clear Health Costs' founder and CEO, Jeanne Pinder, have been trying for years to make prices more transparent — and perhaps even bring them down. Pinder recently wrote about a Louisiana woman who saved nearly $4,000 on an MRI by using CHC data, much of which is crowdsourced. Not surprisingly, prices in New York City also vary a lot. If I hadn't gone comparison shopping, I discovered, I would have ended up getting soaked.

How to find a better price

Using CHC, I looked for a list of local MRI providers. The cheapest scan I found was about $400 — but it was exclusively for patients who were willing to bypass insurance altogether and pay cash. That's common, according to Pinder: Data show that getting insurance companies involved often "raises rates." America's for-profit health insurance system is part of the reason why people in the U.S. pay $3.4 trillion a year for medical care and, unfortunately, don't get impressive results. (Per capita health care spending is Canada is $4,500, or half of what it is in the U.S., and citizens there have better outcomes as well as longer life expectancy.) Being willing to cut out the middleman and pay directly can get you a better deal on your health care, "especially if you have a high deductible," Pinder says. The difference in cost effectively amounts to "a penalty for having insurance." Still, since it made sense for me to pay down my family's deductible, I tried to find a place that would charge my insurance company a reasonable fee. It wasn't easy. As Pinder puts it, usually "if you call someone and ask how much an MRI is, they'll hang up on you."