ST. PETERSBURG — Cory Rider was pulling a paddleboard off a high shelf when something else came down instead: a heavy piece of electronic equipment that struck his collarbone before falling to the floor.His neck and shoulder swelled and hurt, but Rider, 31, tried to wait out the pain. He has neither health insurance nor extra money for imaging to assess the damage."I had no idea how much these things cost," said Rider, who owns a paddleboard business called NinjaFit.No wonder. Patients are routinely urged to help curb health care costs by being good comparison shoppers. But getting straight answers about the cost of medical services is a struggle.Prices depend in part on who's footing the bill. Providers can get more from private insurance than from Medicaid or Medicare, and bill accordingly. And the uninsured, who have no government or corporation to protect them, get socked with the biggest bills.And even in a single provider's network, prices can be all over the map. Need a colonoscopy? In Tampa Bay, in one insurance plan's network, the price tag is anywhere from $600 to $2,400, according to an analysis by the health care software firm Castlight Health. How about a chest X-ray? Prices in the same network are $17 to $536. A mammogram is $14 to $295.But patients who once shrugged off the discrepancies as their insurers' problem no longer have that luxury. Gone are the days when insured patients were responsible only for a small copay. Many have moved to high-deductible plans that require them to pay much more out of their own pockets in exchange for more affordable premiums.But that hasn't made prices any more transparent."Who knows what the actual cost of service is?" said Nancy Metcalfe, senior program editor at Consumer Reports. "They're asking people to be price sensitive and they can't find the price."That may be changing. States are looking at making medical prices more visible. Consumers can use websites to check prices among providers willing to play along. Even medical advertising — still largely silent on price — is changing. Walgreens is promoting its inexpensive new primary care services. Online coupons offer rock-bottom prices for services from cosmetic procedures to dentistry to chiropractic.When his collarbone pain didn't go away, Rider went to an online search engine, typed in "cheap MRIs," and landed on a Tampa-based website called Save on Medical. He found discounted cash prices for dozens of area imaging centers, including Rose Radiology and SDI Diagnostic Imaging. He signed up for a $75 X-ray, a cheaper image, offered by a Pinellas facility, and learned, to his relief, that his collarbone was not broken.Save on Medical works like a travel website, allowing users to lock in the cheapest prices and book appointments online. The imaging centers, which pay to advertise discounted cash prices, benefit by not having to hassle insurers for payments — or losing money on no-show appointments. Most of the site's users have no insurance, though a growing number — currently about one-third — have high-deductible insurance plans and find the site's prices cheaper than their insurers' negotiated amounts, said Matt Schneider, the site's 32-year-old co-founder."Before, your physician would tell you where to go and you'd follow them blindly," Schneider said. "You can see there's a shift in people taking matters into their own hands."• • •Florida got a D on a price transparency report card released last month by an employer group, Catalyst for Payment Reform, and the nonprofit Health Care Incentives Improvement Institute. Not impressive, but better than the F's that 29 other states got.The state has taken some small steps toward making prices more obvious. In 2011, for instance, lawmakers required urgent care clinics to post cash prices of their 50 most frequently provided services. But the state still got poor marks on the report card for failing to make prices at hospitals and other providers more readily available to the public.This month, Walgreens became the first retail chain to expand its in-house clinics — usually the place for minor emergencies like sinus infections — to include diagnosing and treating chronic conditions such as asthma and diabetes. And prices are posted: Diagnostic exams start at $79 for self-pay patients — people who aren't using insurance.More than 300 of its Take Care Clinics, including those in the Tampa Bay area, employ nurse practitioners and physician assistants who can write prescriptions and order tests. Most insurance plans are accepted.Dr. Alan London, chief medical officer for the clinics, said its cash prices are lower than most offered in the community."Affordability is a hallmark of our business," he said.• • •When you buy paper towels or milk, it's easy to shop by price, because you know exactly what you're getting. But how do you know if your bargain MRI or teeth cleaning is as good as the higher-priced options? Or might you even find that the lower-priced option is more to your liking?There are websites that purport to rate physicians and hospitals, but their criteria can be squishy. "Patient satisfaction'' can be measured by time spent waiting to see the doctor — not necessarily whether you received the best standard of care. That's tough for people not trained in medicine to judge.Dr. Peter Ubel, a physician and behavioral scientist at Duke University, wrote in the Atlantic magazine this month that focusing on prices may backfire. Patients don't shop for health care the way they shop for toasters, he noted. Many assume, sometimes wrongly, the most expensive service is the best. "We need to stop naively assuming that price transparency will function in health care the same way it does in other parts of the economy," he said. "What works for toasters won't necessarily work for MRIs."Castlight Health, one of the pioneers in the price transparency business, sells software to self-insured employers, whose workers can then compare the costs of various health care providers. Senior marketing manager Christine Evans said it's difficult to get data showing patient outcomes for specific doctors. So Castlight provides information such as the number of a specific surgical procedure a doctor has performed to help clients judge quality.Schneider, the Save on Medical co-founder, said shopping won't work for all health care services, certainly not for emergencies. For now, he's sticking to imaging and other diagnostic testing. The quality of these services can vary depending on the skill of technicians and the quality of the machines. But the procedures are not done on an emergency basis, giving patients time to research the providers. Save on Medical has begun using a "docometer" to rate patient satisfaction.But when funds are limited, price may be how you choose health care.Ashley Fraigun, a 30-year-old yoga instructor and runner from Tampa, has no health insurance. When her right hip began throbbing after long runs, she tried to nurse the injury on her own. "I was nervous about how much this would cost," she said.Finally, she went to a walk-in clinic, where the staff told her she needed an MRI. Fraigun's brother had just paid $300 for one — more than she could afford — so she went online and found Save on Medical. Like Rider, she got an X-ray for $75."It's hard. Rent, all the other life expenses," she said. "I'm glad there's some self-pay options."Last week, Fraigun got her results. She was told she has hip bursitis and should take ibuprofen and refrain from running for about six weeks — the least expensive treatment plan she could have asked for.Note: This story has been updated to reflect the following correction: Two customers of Save On Medical, a Web site that advertises prices on imaging services, paid $75 for X-rays. A story Monday reported another type of image.