Lela I find you comparison of gas prices to medical care cost to be absurd.  When I drive and need gas I may or may not have a choice as to purchasing gas at the station I stop at when it is the only station for 30 miles. Likewise I have never seen the cost of medical services laid out on a price sheet when I entered the emergency room.  
You imply a person could simply forgo medical treatment if the cost was to high. Really, a person might have that opportunity only when the procedure  is an elective procedure.  When it is a more common need for medical attention as a broken limb, heart attack, or accident victim  I doubt there is many choices available to the patient; you get treated at what ever the unknown cost is. You just don't leave the hospital and shop around for the best price to provide required treatments when you or a family member needs care right now.  On more than one occasion I and thousands have paid fees above and beyond the 20 % co-pay you refer to out of pocket.