Out-of-pocket hospital costs without insurance: What to expect?

Does anyone actually know how the rules work these days? A family member of mine just ended up being hospitalized—without any supplemental insurance—and the doctors are estimating about $667 of inpatient stay. So, if the person stays for 10 days, does that mean the bill is going to be $6667? And what about all the tests and extra stuff... or will the total just be $667 regardless of the length of the stay? I honestly can't make heads or tails of it anymore. It feels like they've gone totally irrational... I don't understand why they keep deducting my hard-earned money from my paycheck every month if I have zero coverage as a standard policyholder. Also, if someone decides to pick up a supplemental insurance policy now, how long is the waiting period before it actually kicks in for hospital stays? I tried digging through the Medicare website, but I couldn't find anything remotely helpful.

Just so you know, there's a cap of $2,000 per visit for reimbursement... and that supplemental coverage stays valid for 15 days after you set up the agreement.

I’ve got a question about the bills. I just spent 10 days in the hospital getting surgery. Is this whole thing going to be $667 or am I looking at a much higher number?

Forgot to mention, this was actually a workplace injury.

Once a workplace injury is officially recognized, you aren't paying a dime. There are no co-pays and zero out-of-pocket costs; everything is covered entirely by the Occupational Safety and Health Administration (OSHA). I should clarify one thing: we are talking about an injury formally classified as a work-related accident, not just some minor mishap that happened while you were on the clock. Your supplemental health insurance? Irrelevant. You won't be footing the bill for a single cent regarding the treatment of a recognized workplace injury.