What does it actually cost to take a trip through this tube? (Photo by Flicker user liz west , used under a Creative Commons license)

Trying to shop around for the best deal on health care services can be maddening. So Lisa Aliferis, a health care reporter for KQED News in San Francisco, came up with a simple idea: ask people what charges they're actually seeing on their bills and try to make sense of the madness.

We already know there's a huge variation in what hospitals charge for the most basic health-care services, based on their internal price listings. For instance, the average cost of a primary care visit ranges from $95 in Miami to $251 in San Francisco, according to a comprehensive study of employer-provided insurance coverage earlier this year. A first-of-its-kind data release from Medicare last year showed similar variations in the prices charged by hospitals.

But insurers and patients rarely pay the listed price. Aliferis — in a partnership with KPCC, a public radio station in Los Angeles, and Clearhealthcosts.com, a health transparency startup — tried to capture information of actual prices that people, who reported the information anonymously, were seeing on their medical bills — breaking down what the insurers were charged and what people actually paid.

She found big price differences within the same state, based on facility and insurance status. Private insurers in the Los Angeles and San Francisco areas paid anywhere between $128 and $694 for a mammogram, a procedure performed about 38 million times a year. A Medicare patient was charged $255 for a lower back MRI, while another uninsured patient was charged $6,221 at an academic medical center for the same procedure, Aliferis wrote.

Her database relies on reports for individuals and hasn't been without its problems. The most common complaints, Aliferis writes, is that it's still hard to comparison shop — it's not going to be easy as buying a retail item online. Also, the price of a health-care service doesn't say anything about the quality of that service. In health care, there's really no correlation between the two.

Another big finding came from the patients themselves — frustration. Frustration toward "their inability to get a bill that made sense (or find an accurate price in advance)," Aliferis wrote in the policy journal JAMA Internal Medicine.

Past research suggests that people will save money when they're able to shop around for health-care services — but it also shows most people with access to price transparency tools don't actually use them.

The interest in the project so far has been high, Aliferis wrote in her journal piece. The group has received hundreds of submissions since launching the crowd-sourced database in June — including some from doctors themselves, and it's been searched thousands of times.