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.

Caitlyn Mai thought she did everything right. She called ahead to make sure her insurer would cover her cochlear implant surgery. She thought everything went according to plan but she still got a bill for the full cost of the surgery: more than $139,000.

What Caitlyn did next is a reminder of why a beloved former guest once said you should “never pay the first bill.” This episode of “An Arm and a Leg” is an extended version of the July installment of the series, created in partnership with NPR. Hey there — One morning when she was in eighth grade, Caitlin Mai did what she always did when she woke up.

It was obvious, because on this Beatles tune she’d cued up, Eleanor Rigby, the vocals are almost all on the right-hand side, and she couldn’t hear them. Yeah, confusing. And then she tried getting out of bed.

With that vertigo, Caitlin could barely walk at all. She had no sense of balance — that actually relies on a mechanism inside our ears. Later, doctors found she had lost 87 percent of her hearing on the right side.

She had to learn how to walk all over again. That was eighth grade. Caitlyn made it through high school, in Tulsa where she grew up without a lot of accommodations.

Catilyn’s 27 now, she works as a legal assistant in Oklahoma City. Her hus.