Copay is your cost for each visit. Depends on the service. It might be $20 to see your doctor. $40 for a specialist. $300 if you’re admitted to the hospital.

Deductible is the amount you have to pay before insurance kicks in. Say yours is $1500. In some plans that’s for medical services beyond visits. So seeing the doctor my cost you $20 as a copay and insurance pays the rest. Now you need an X-ray which is $300. You have to pay that and that counts as part of your deductible. Now they send you for an MRI that’s $4000. The first $1200 is on you (the rest of your deductible), then the insurance covers the rest.

Lots of fine print. Some plans pay everything past the deductible. Some pay 80% of that and you still pay 20%.

In some plans the deductible only applies for stuff like X-rays, MRIs, and surgeries. Other plans it may apply to other basic visits.

Your health insurance has doctors and clinics that they have a contract with that covers rates. These are in network and normally a lot cheaper for you. If you go to a different doctor not on their list, it’s considered out of network which means at least two worse things. One is lower coverage, and the other is insurance only covers at their “normal” rate. Say you see an allergist, and their bill is $200. Insurance says “we cover 80% of our standard rate. Our standard rate is $150 so we may $120” So you end up owing 80 to the allergist.

If you have a genuine emergency while traveling (eg chest pain) on a decent plan you can get emergency service even at an out of network hospital but you may have to call first.