The cost of a piece of metal in your eye.
$300 for 5 minutes, but you can get a lube and an oil change on your car for $30 and that includes 5 quarts of oil, a filter, and any other required fluids.
The obvious difference is price competition. People shop price for car repairs but not for medical procedures. Most people only pay the co-pay, no matter what the doctor charges so there is no incentive to shop for a good price.
While healthcare costs are going up 10% per year, prices on elective procedures like LASIK, dental implants and cosmetic surgery are going down.
I heard a story on NPR about a guy with catostrophic coverage who tried to price shop for all his non-emergency healthcare. He would call up doctors offices and ask how much for XYZ procedure and it was next to impossible to get the prices in advance so he could choose the cheapest doctor. In contrast, you can see prices advertised in the newspaper for elective medical procedures or car repairs.