the only way an insco can give you a price before service is if you give them the billing code/s for what is being done and then all they can give you is their allowed amount/s, after that it all depends on your plan(100%, 90%/10%, 80%/20%, High Deductible) and if you've met your deductible people absolutely must read their policy EVERY YEAR to see what has been changed but 95% never do
also you have the RIGHT to ask your doctor's office the price range for an office visit even if it's not posted
if they won't tell you, you need to find another doctor