They're really common screenings, especially for people who are over 50. More than 10 million people have one each year.

 "Especially the prep I'd say is not, uh, very enjoyable," recalls Patricia Carmona, of Montgomery County. "I'm trying to postpone it!"

Carmona is talking about the oh-so-beloved colonoscopy.

"I have some history of colon cancer in the family, so it's like a routine check up for me," she says.

Colonoscopies around Philadelphia: from about $800 to $8,000?

A routine procedure, perhaps, but the prices are far from it.

In the Delaware Valley, prices appear to be all over the map, ranging anywhere from $800 to $8,000 dollars. That's based on information from a dozen people who entered what they were charged and what they paid for a colonoscopy into WHYY's PriceCheck database (a caveat: some of these entries may not be directly comparable because, as we'll explain, of what's included in that price and in some instances, what's involved in the procedure).

The reported cash prices at 15 facilities who responded to WHYY's price check survey ranged anywhere from $900 at Mid Atlantic GI consultants in Newark, Delaware to $2100 at Cooper Digestive Health in Camden, New Jersey (WHYY reached out to both places but did not get a response).

Richard Gundling, with the Health Care Financial Management Association, cautions against making too much of that list price. His organization created an explainer. He says the way health care works, those initial, listed cash prices for colonoscopies or for any other medical procedure are just a starting point.

"So much of the differences [in actual price] can be what your insurance is and the negotiated rate," he says.

Insurers and providers negotiate individually on the price of a procedure. These negotiations are generally kept confidential, but what that means is the actual bills may vary a lot from place to place, based on a combination of one's insurance and the selected provider.

But for Patricia Carmona, she learned that prices can vary the hard way.

"The [overall] bill was over $10,000," she says. "I was shocked because I didn't know. I thought that a colonoscopy was a colonoscopy, and that there was a rate that didn't vary by provider."

Carmona hadn't paid attention to the cost or where to go until she went in for a colonoscopy in 2012, recommended by her doctor, under a new insurance plan. It meant she had to shoulder more of the cost of her care - 20 percent.

She wound up paying about $1600 out of pocket. A coworker, with the same insurance, went elsewhere and paid less. Meanwhile, her sister living in another state also received a colonoscopy for several hundred dollars less.

Unexpected expenses: physician, anesthesia and facility fees

As Carmona also discovered, colonoscopies typically involve several components - components that may vary from person to person - that are often billed separately.

She was unprepared, for example, for the different bills she the later received for the procedure.

"I called them [the hospital] and said, 'why are you charging me twice?' Because it seemed they were charging me twice," she says. "But then they explained that's not the way it works."

Medical bills are complicated, but Carmona's experience is a common one for colonoscopies. She received separate bills for the physicians involved in her procedure and then for the use of the facility rooms and equipment.

In her case, several doctors were involved in the procedure. For example, one oversaw anesthesia, another the colonoscopy itself. During the procedure, as often happens, the doctor discovered polyps or growths, which were removed and then examined by another doctor. She also had another related endoscopy.

Those doctor fees alone came out to more than $3,000, but her insurance rate brought that down to about $2,500. Given the details of the cost sharing on her insurance, Carmona paid about $500.

But that wasn't it.

The other big charge was for another $7,000. That was for what's called the facility fee.

Listed in her statement from Thomas Jefferson University Hospital, where she went, these fees included the use of the operating room, the recovery room, the pharmacy and the lab.

Keep in mind, that $7,000 dollar mark was what Gundling and others often refer to as the starting point.

"So at the end, the negotiated [insurance] rate was $5,900," she says. "Insurance paid 80 percent of that. I had to pay the rest."

The hospital turned down a WHYY interview request, but Gundling says these facility charges are typical for colonoscopies, and that they're often higher at big hospitals.

"Academic medical centers may have a higher true cost of providing the service because of the greater facilities and staffing and those type of things that they have compared to maybe an out patient center that may have lower cost but may not be able to do as quite complicated cases."

Gundling also says hospitals often structure fees in a way that cross subsidizes other important health services, charity care and research.

The price may also vary depending on the level of anesthesia used, according to Dr. Neel Shah, an obstetrician-gynecologist and assistant professor at Harvard with an interest in health costs.

Shah says with colonoscopies especially, people may encounter unexpected sticker shock when they get their bills. That's in part because under the Affordable Care Act, insurance fully covers colonoscopies if it's preventive. That could change, mid-procedure.

"You do a screening of a colonoscopy because you're' looking for polyps and other things that might be suspicious," says Shah. "The trick is if you find something that is suspicious and needs a biopsy, that biopsy might be billed separately."

Shah says in general, however, prices for colonoscopies and other medical procedures may vary from place to place because, well, they can.

"You know it's just the market at work. It's the same reason why different restaurants can charge different prices for a hamburger," he says. "The difference with a hamburger is you kind of know the quality you're getting as soon as you bite into it. With a colonoscopy, it's much harder to know the quality."

That quality, says Shah, usually is not well connected to price in health care.

Lesson learned

As for Patricia Carmona, she says she learned her lesson after getting those colonoscopy bills.

"Ever since that moment, I started every time I needed a procedure or had to get an x-ray or whatever, I always called ahead to get an estimate for the pricing," she says. "But it's a struggle, it's really, really hard to get this information."

Her colonoscopy experience also better prepared her for dealing with a fragmented payment system when her daughter recently broke a toe.

"You get charged by the hospital fee and then you get the different physician charges." she says. "I got charged by the hospital for x-rays, charged by the x-ray physician and then charged by the doctor at the hospital."

Carmona's doctor tells her she's actually due for a colonoscopy again soon. This time around, she's says she'll be calling around to different providers and asking up front about those facility, physician, consultation and anesthesia fees.

Shah says that while it might be difficult for someone like Carmona to get an exact price in advance, asking the right questions - such as 'is that the total cost?' - can help prevent major sticker shock down the road.

"Because sometimes there's a facility fee included separately, sometimes there's not. Sometime there's a separate provider fee or separate anesthesia fee or separate lab fee," says Shah. "So usually ahead of time, most people [providers] are going to struggle to give you an exact dollars and cents quote, but they should be able to give you a reasonable estimate, so you have a sense of what you're getting into."