Imagine being told you had to go to a special store where you would be surrounded by people who tell you what to buy and and you don't really have any control or knowledge of whether or not you need these things but are just told that it will be good for you. There are no prices on anything. You receive a bill weeks later with vague descriptions and seemingly arbitrary prices. A seemingly simple visit to this "store" lasting just a few hours can generate a bill of thousands of dollars. Others who go to the store for the same reason will receive different prices. You can't question what you received or how much it cost.
Welcome to the US health care "system". You are the consumer and your role is to pay the bill (or arrange for expensive insurance) and possibly receive some benefit from the system (although all of the other 21 developed countries have better outcomes from their health systems than the US).
Prices are set secretly and only disclosed to individuals after the service. There are many different prices depending on how your bill is paid. If you have some insurance protection or are covered by a government program, they may be able to negotiate a lower price. If you don't have any "coverage", you are often charged the highest price.