Free market economics tell us that the fair value of something is determined by free buyers and sellers, each acting in their own self interest..  Free consumers can negotiate a better price, or simply take it or leave it.  Hospitals, however, don’t give the patient any choice in the matter, other than to refuse treatment and possibly DIE.  If you are uninsured, or if your insurance carrier doesn’t have a contract with that provider, you can find yourself bankrupt and never see it coming.
Here is a quote from a CBS Evening News (I’ve put the link at the bottom of the page) report:

“Most Americans know that if you get sick enough to go to a hospital, it's going to be expensive. But you may be surprised to learn that hospitals all over the country charge their highest prices, by far, to those who can afford it least — the 46 million Americans who don’t have health insurance. *
Hospitals charge uninsured patients two, three, four or more times what an insurance company would pay for the same treatment. And, when the uninsured can’t pay, they often find themselves the target of collection agencies or in bankruptcy court. “

This price discrimination applies to people with the wrong insurance as well (what the insurance company calls ”out-of-network”).

In a nutshell, here's how it works:
The hospital will correctly claim they bill everyone the same amount.  True, but the amount they accept as 'payment in full" varies tremendously.  For instance, an MRI here costs roughly $1600; the hospital bills for $3500 and insurance pays $1600 and all is hunky dory.  But if you go to a hospital not on your list of approved facilities, you will personally be on the hook for the entire $3500, even when you get your insurance company to pay for it!    They will harass you, send you off to collections, and eventually put it on your credit report.  The one thing they don't do is sue you for the money and get an actual judgement against you.  They can't win in court, so they try to scare people into paying up.

My husband is a lawyer and we are not intimidated.  He would love to get this case in front of a jury.  No jury in the world will give them that extra money when it is obvious the charges are way beyond "reasonable and customary", and we might even get an award for sticking it to them!

http://www.cbsnews.com/video/watch/?id=1364621n