Websites that let you price shop medical procedures or products

I’m a nerd. I like looking up used car prices on autotrader and for fun.

I noticed in the last few years websites devoted to medical procedures are starting to show up too. This is good because there have been websites devoted to cost comparisons of homes, cars, consumer products, tickets, etc. where you can compare costs on a product form various vendors, but not really any devoted to medical procedures or devices. Plus a major criticism of cost in US health care is that because there is no real cost comparison shopping, there is no incentive to lower costs or improve quality.

So what all are there now?

Good for medications

Good for various medical procedures
I figure it is good to know for research if I ever have a medical condition not covered by insurance.