The answer is "it depends". There are so many hoops and loopholes and gotchas built into the system that 2 identical people with the exact same background and ailment(s) could go see the exact same medical staff and yet still end up having to pay 2 completely different amounts for their care. But it's more complicated than that, because there are a myriad factors that come into play (insurance versus none, location/state of residence, etc) so there's no one concise and accurate answer to these types of questions.

Most non-wealthy people who don't have insurance, but who don't qualify for government/public medical care, simply go without care. Or they use the emergency room loophole to get some kind of treatment. The loophole, with lots of nuance and caveats, is that the emergency room has to at least give you enough treatment to temporarily stabilize your condition, regardless of your ability to pay.

For check-ups and counseling - In a lot of places that sort of stuff requires you to pay up front. You can sometimes haggle or work out a payment plan. If you're poor enough to qualify for government aid, it may be free. Otherwise, you're expected to have insurance and pay the co-pay. If that doesn't apply, these places usually have a "cash" price that's slightly more affordable, but still usually require payment ahead of time.

For meds, you basically always pay up front. There's really no concept of pharmacies providing medications in a manner where you can pay later. No money means no meds. It's also ridiculous to even ask how much a person would expect to pay for meds, it could be as little as a few USD to thousands, really depends on the meds, quantity needed, location, etc.

Xrays - This is where debt might actually come into play. You usually pay for these after the fact. If you go to the doctor, you might have to pay the standard fee (or copay) up front, but all the other services/tests/etc are charged after the fact. So you'll end up getting a bill after you've gotten the xray and consultation. To be honest, I don't know the average out of pocket cost for an x-ray if you don't have insurance, but it would differ from location to location and region to region. If you don't pay that bill, you'll get harassed and most likely you'll have to change doctors because the office you owe money to won't see you again until your debt is paid or you've worked out a payment plan.

For people with insurance, there's pretty much always a maximum yearly out of pocket amount, after which things are basically all paid for by insurance. Again there are nuances and caveats. And the maximum out of pocket varies by insurance policy, number of people insured, etc, but $8,000 - $20,000 are not uncommon amounts. To be honest, I don't even know what mine is, I've never actually reached it. Not everything is covered by the maximum out of pocket, though.

$27,000 medical debt could possibly be from someone who was uninsured or it may be several years of medical debt.

To give you an idea of how crazy the system is: I had a hairline fracture several years ago and what was deemed as "good" insurance. By the time everything was done, it ended up costing me around $3,000 out of pocket. That's for co-pays, x-rays, medication, etc over the course of months.

On the other hand: A family member of mine had a heart attack, required emergency surgery, had no insurance, and had no money to pay for anything. In the end cost them less than a few hundred USD out of pocket. Hospital wiped the debt clean. Government programs and drug company programs paid for meds. Eventually disability stuff kicked in and took care of everything else.