Also even if you want to understand, the CPT coding books are behind a pretty substantial paywall. It's like $150 for a copy of the latest reference book. You might get someone to explain it to you, your best bet would probably be to call your insurance company and ask them to explain your bill, followed by the department's billing office. I say this because trusting the provider to check the bill is a conflict of interest.

As for insurance price comparison, most insurer websites I've used in the last 5 years have had some kind of feature to compare average prices with that insurer. It's worth knowing for the hospitals around you. But even if you do with medicine it's difficult to know what services you're going to need, the treatment plan may change dramatically after diagnosis. For instance you may think you are going into the hospital for some foot pain, find out you broke your foot, and come out with a cast and crutches.

One big tip: do not go to the ER unless it's a life threatening emergency (chest pain, stroke symptoms (slurred speech, sudden loss of balance, drooping face, confusion, trouble seeing), late pregnancy complications, blurred vision, trauma, severe burns, etc.). Urgent care facilities are about 1/5th the cost of the ER. If you set foot in the ER you can usually expect it to be at least a $2,000 bill and how much you have to pay will vary greatly based on your insurance coverage.

Lots of hospitals will offer prompt payment discounts or will even reduce the bill if you agree to go on a payment plan instead of it going to collections.

I would still start with an itemized bill and make sure each charge is correct before I did this though. Then you should be able to stack the payment discounts on top of this.