We just went through this a few weeks ago. DD got sick with pink eye and an ear infection. The resort (CBR) referred us to Centra Care, which offers a free shuttle to the clinic.
It's $160 for an office visit, which must be paid in full if they don't take your insurance or if you're uninsured. Special care - lab work, etc - is extra. There's an attached pharmacy to have prescriptions filled, and they do not accept insurance but will give you a receipt to get reimbursed when you return home. My DD got eye drops and an antibiotic syrup, and it was $100.
I was very unimpressed with Centra Care. The front desk staff was appalling. People would call, and this one receptionist would tell them there was a 4 hour wait to be seen because the clinic was so busy (there were 3 of us waitijng), and then when she hung up she laughed with the other one about lying about the wait time to discourage people from coming.

She told another caller that called in that there was a 30 minute wait for a shuttle pick up at AKL, and as soon as she hung up she was on the walkie talking talking to a shuttle driver, whom she had apparently sent to
Walmart to pick up a watch battery for her. They kept going back and forth because he couldn't find her model number, and all I could think about was the poor person at AKL waiting to get to a doctor.
The doctor and nurse we saw were fine, but very rushed even though it wasn't a busy night by any means. There were never more than 3 people waiting to be seen in all the time we were there, and that includes us.
I had to pay in full because they didn't accept our insurance, and two weeks later they sent me a bill for $45 more that doesn't say what it's for and I haven't been able to get anyone to return my calls and explain it. It's in dispute now, so atleast I don't have to pay it until it's sorted out, but it's definitely a hassle I don't need.
Next time, if God forbid there is a next time, we'll be using the rental car to go elsewhere.