Whether you're negotiating with a used car dealer, carpenter or a cardiologist, nothing says lower my bill better than "I'd like to pay now with cash." Most doctors pay thousands of dollars each year to strong-arm patients into paying their bills. In many cases they have to hire attorneys or collections agencies to recoup the unpaid money. Doctors also don't like patients who pay by credit card, because their processing fees can be huge. Receiving cash saves the doctor a lot of time and trouble. When someone pays cash up front or within 30 days, chances are they can negotiate a better deal, perhaps up to a 40 percent discount [source: Lee and Brody].