A colonoscopy might cost you or your insurer a few hundred dollars—or several thousand, depending on which hospital or insurer you use. Long hidden, such price variations are supposed to be available in stark black and white under a Trump administration price transparency rule that took effect at the start of this year. It requires hospitals to post a range of actual prices—everything from the rates they offer cash-paying customers to costs negotiated with insurers. Many have complied. But some hospitals bury the data deep on their websites or haven’t included all the categories of prices required, according to industry analysts. A sizable minority of hospitals haven’t disclosed the information at all. While imperfect and potentially of limited use right now to the average consumer, this trove is, nonetheless, eye-opening as an illustration of the huge differences in prices—nationally, regionally, and within the same hospital. It’s challenging for consumers and …