I got a MRI on my lower back in April.
Going to my insurance provider I was able to get a list of places to get a MRI near me. Since I kind of live in the boonies, everything was 45 to 60 miles away so it was a difficult search of an unfamiliar area.
Anyways, going through this list I called them and made sure they accepted my insurance plan. This is a super small business plan that costs me $1400/mo. On top of this it has a huge deductible.
The magic words are "contracted rate" - call up the office and get the specific code for the procedure that your doctor prescribed. Call up your insurance company and ask them, at this physician, what is the contracted rate for this code? They will put you on hold for 10-30 minutes and come back with a number.
Doing this 4 times I had 3 places that were between $1100 and $1800. That is my out of pocket cost for the procedure. Then I found one place that had a contracted rate of $440. That's a quarter the most expensive place!
There is NO UI or no realistic way to do this. This process took me about 5 hours of work on the phone to complete.
As a bonus, you can ask the physician what the insurer pays them for the procedure. Once you have all of the numbers in front of you it's a bit easier to tell why one place was 25% the cost of another place.
Anyways. Contracted rate and medical procedure codes. Those are the things you need.