system
Given the following post, respond as if you're commenting on Reddit:
human
eli5: What is a copay and what is a deductible?

I have no idea how the US health insurance industry works other than that it is kinda wack. Please inform me.
gpt
A co pay is the portion of the appointment or procedure that you pay every time you use it.  For example, you might have a $20 copay for a doctors office visit.  That means every time you go, you pay $20.

A deductible is the portion of everything above that you have to pay until it's met.  So lets say you have a $1000 deductible, then you go to the doctor and you pay your $20 but the doctor bills the insurance for a $200 visit.  If your deductible is not met, you will have to pay the $200.  Well, there is usually a discount, but to make it simple.  Once you reach the deductible then the insurance starts paying.

It gets a bit more complicated in that some appointment types do not have the deductible applied.  Like most insurance companies give you 1 "well being" visit with your doctor for a physical a year and the deductible doesn't apply.  So you don't have to pay for it except maybe your copay.