How can a two-hour treatment for a bee sting end up costing a patient $12,000? Prices can soar when the patient goes through a barrage of tests and insurance doesn’t cover the bill, but Sylvia Rosas’ case is shining a light on the cost of health care in the country.

It all started with a simple bee sting in her yard in Florida. Rosas had allergic reactions to stings in the past, but didn't have an EpiPen, so she went to the emergency room, CNN Money reported. Several doctors looked at her sting and ordered blood tests and an EKG to ensure she wouldn't have a reaction. The visit, which took less than two hours, happened to be at an out-of-network hospital, so her insurance wouldn't cover it. Rosas had to pay the bill out of pocket.

Now, she’s second-guessing when she needs to see a doctor so she won’t wind up with the bill later.

>> Read more trending news

Rick Brown found himself in a similar financial situation, CNN Money reported.

He twisted his ankle. After trying to treat it at home to no avail, he went to his local emergency room, on his own crutches, and was seen by a physician assistant. Brown had an X-ray done on him and was given a splint and a prescription, with a suggestion to see a specialist for the fracture.

He was billed $2,600 for the ER visit. Then, he received a separate bill for $5,700 from the doctor’s office. Insurance paid half of the ER bill, but denied the doctor’s charges because the person who saw him was out-of-network.

Brown said that if he would have known that the bill wouldn’t be covered, he would have waited a few days longer to see someone else.

Officials with the Health Care Cost Institute say ER visits cost an average of $1,917 in 2016. That's more than 31 percent higher than it did four years before.

The amount billed by the hospital usually covers the facility fee and some tests and services, CNN Money reported. But it usually doesn't include the cost patients incur for actually seeing a doctor, which is usually billed separately.

The big question is: Why does it cost so much?

Emergency rooms are seeing more patients, and those patients have severe medical problems.

People with cuts and fevers will more likely go to urgent care locations. Patients with chest pain and those suffering from asthma attacks are seen in emergency rooms, and those conditions are more expensive to treat, CNN Money reported.

Emergency rooms also have access to expensive equipment, like CT scans and MRIs.

So where does that leave patients who need care, but don’t want to gamble with their finances?

First, experts told CNN Money that patients don't need to sign paperwork with the ER that promises to pay in full just to be seen. Federal law says ERs have to screen and stabilize anyone who comes in.

Second, if you're stuck with a bill, speak with the health care providers. Prices can be negotiable, CNN Money reported. A professor of surgery and health policy at Johns Hopkins University found that hospitals mark up some services as much as 340 percent more than Medicare allowances.

"Prices are highly fluctuant and often negotiable," Martin Makary told CNN Money. "As with new cars, people are not expected to pay the sticker price."