Health care — and how much it costs — is scary. But you’re not alone with this stuff, and knowledge is power. “An Arm and a Leg” is a podcast about these issues, and is co-produced by KFF Health News.

Some people who expected their health insurance to cover some out-of-network care have been getting stuck with enormous bills. One Kansas City, Kansas, couple paid thousands of dollars out-of-pocket and up-front for care. They expected to get a partial reimbursement from their insurer.

So, they were shocked when instead they got a bill saying they owed even more than what they’d already paid. It turns out, a little-known data firm called MultiPlan was working with their insurance company to suggest cuts to their coverage. MulitPlan says it’s helping control ballooning health care costs by keeping hospitals and providers from overbilling.

But it’s often patients left paying the difference.In this episode of “An Arm and a Leg,” host Dan Weissmann breaks down this confusing world of out-of-network care with New York Times reporter Chris Hamby, who recently published into MultiPlan. Hey there! Paul and Kristin live in Kansas City with their two kids.

Kristin and their daughter, the older kid– they have some complex medical issues, need to see some specialized folks. And some of those folks don’t take Kristin and Paul’s insurance. They’re “out of network,” so Kristin and Paul pay out of pocket– a lot.

Maybe $20,000 a year. BUT their health insurance .