I would pay a subscription fee for such a service.
The premium is what you pay every month for the plan subscription.
Your deductible is the amount you pay before insurance does anything. Some plans are 0 deductible, 500, 2000 etc.
Then after you fulfill the deductible, your insurance maybe covers 80% or 90% of expenses. So if you get a $1,000 medical bill, you only pay $100 or $200.
A co-pay is a separate fee you pay to see the doctor. You pay every time you see the doc.
Out of pocket max is the maximum amount you pay in a year. So if it is $12,000, and you get a huge $500,000 medical bill, you will only pay $12,000.
Good luck!