Perhaps confusingly, they charge both. Most insurance requires substantial "co-pays" where you pay a good chunk (20% is common, but it varies, often even within

Perhaps confusingly, they charge both. Most insurance requires substantial "co-pays" where you pay a good chunk (20% is common, but it varies, often even within a plan depending on what you're paying for) of just about every bill until you hit some very-high "out-of-pocket max" (usually there's one for individuals, and a higher one for families) and then insurance picks up everything, or you pay 100% until some total-spending value for the year is reached, then it becomes like the prior situation until the out-of-pocket max. Though most insured people don't really have options to shop around. You go to the few places your insurance covers, which is usually 30-60% of providers in a small geographic area. Which is why the "we want to protect your choice!" opposition to healthcare reform is so damn weird. Most people already have very little choice, in practice, and a lot of the "choice" we do have isn't anything desirable ("which of these shitty insurance plans I can barely understand and am not confident I can meaningfully compare, would I like to suffer through?").