Insurance companies negotiate with hospitals and doctors the price of every treatment, procedure and medical service. That price differs from hospital to hospital — even health plan to health plan. Vincent Wartner/Science Source hide caption

itoggle caption Vincent Wartner/Science Source

Ouch! Jeffrey Craig Hopper got good emergency treatment after being hit in the eye with a baseball in June. But months later he was slapped with an extra medical bill he never expected. Jennifer Hopper hide caption

itoggle caption Jennifer Hopper

A nurse at the University of California Medical Center in San Francisco protests lack of Ebola preparedness in October. The issue will be the focus of national demonstrations Wednesday. Justin Sullivan/Getty Images hide caption

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Ebola patient Amber Vinson arrived by ambulance at Emory University Hospital on Oct. 15. Now healthy, Vinson was discharged from the hospital Tuesday. Kevin C. Cox/Getty Images hide caption

itoggle caption Kevin C. Cox/Getty Images

An official at the University of Michigan Health System in Ann Arbor says its mix of patients helps explain the infection rates. Scott C. Soderberg/Courtesy of University of Michigan Health System hide caption

itoggle caption Scott C. Soderberg/Courtesy of University of Michigan Health System

Nina Pham, shown here in a 2010 college yearbook photo, became infected with Ebola virus while caring for Thomas Eric Duncan in a Dallas hospital. Courtesy of tcu360.com/AP hide caption

itoggle caption Courtesy of tcu360.com/AP

Dr. Wvennie MacDonald, the administrator of the JFK Memorial Hospital, has helped put new procedures in place to keep Ebola out, including a triage station to identify possible Ebola patients at the front gate. John W. Poole/NPR hide caption

itoggle caption John W. Poole/NPR

Ideally, the best place to care for someone ill with Ebola is at the end of a hall in a room with its own bathroom, anteroom and entrance, says Dr. Jack Ross of Hartford Hospital. Jeff Cohen/WNPR hide caption

itoggle caption Jeff Cohen/WNPR

Traffic moves past Texas Health Presbyterian Hospital in Dallas, where a patient showed up with symptoms that were later confirmed to be Ebola. Mike Stone/Getty Images hide caption

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Kevin Wierhs and Susan Johnson confer about what works and what doesn't in managing diabetes. Sarah McCammon/Georgia Public Broadcasting hide caption

itoggle caption Sarah McCammon/Georgia Public Broadcasting

Michael Granillo and his wife Sonia await treatment at an emergency room in Northridge, Calif. Anna Gorman, Kaiser Health News hide caption

itoggle caption Anna Gorman, Kaiser Health News

The headquarters for University of Pittsburgh Medical Center and Highmark Blue Cross/Blue Shield dominate the Pittsburgh skyline much as they organizations have dominated health care in the region for decades. Jeff Brady/NPR hide caption

itoggle caption Jeff Brady/NPR

Television trucks converged on Mount Sinai Hospital in New York on Monday after it announced that it was screening a patient for Ebola virus. Stan Honda/AFP/Getty Images hide caption

itoggle caption Stan Honda/AFP/Getty Images