Many health insurance plans have a yearly cap on how much you pay out of pocket. So you might pay 20% up to a few thousand dollars, and then get 100% coverage after that.
Actually, with the passage of the ACA, the limit is a requirement for all health insurance plans (a few were grandfathered in, but they will disappear over the next few years).
It goes up each year (adjusted for inflation), but as an individual, your maximum out of pocket (includes everything: deductible, co-pays, co-insurance, etc) is ~$6,750.
I'll never forget the year I had laproscopic surgery to remove my gallbladder, not because of the experience (although being asked for $3000, in cash, before they'd let me into the OR, was interesting, but welcome to America), but because I ended up hitting my $5000 or so out-of-pocket maximum, between that and co-pays for a few other visits. For the remaining 6 months of the year, I joked that I was living it up Canadian style, and actually visited the doctor to get regular exams and to get medicated for influenza, you know, the things everyone should do, but a large double-digit percentage of Americans can't. Ahh, the good life...
It goes up each year (adjusted for inflation), but as an individual, your maximum out of pocket (includes everything: deductible, co-pays, co-insurance, etc) is ~$6,750.