Price is irrelevant. Don't tell your patient that a lab fee will be XXX dollars, or even that there will be a lab fee. Remember: your patient is too stupid to understand the details of his/her care. If a test can be done, the test will be done. If your patient is living paycheck to paycheck, facing homelessness or suicide over a few hundred dollars, that doesn't matter. Run that $149 biopsy just to be sure, because money is nowhere near as important as someone's health care. (Unless they can't pay at all. Then, don't treat them at all.)
Radiation is irrelevant. Don't warn your patient that X-rays cause cancer. It's more important to be sure if they've broken the rib or not. Even if you won't treat the broken rib, it's your responsibility to tell them either, "It's broken, so take it easy for 6-8 weeks," or, "It's not broken, but take it easy for 6-8 weeks." Leaving out the first part of either of those sentences is not an option. Remember: it's better to die of brain cancer at 57 with two tooth fillings than it is to live until 82 with four tooth fillings.