I don't think most people do.
There is no premium for most people.
For inpatient hospital stays, there is a $1,316 deductible per benefit period
Standard Medicare Part B premium is $134 per month.
A deductible.
Pay 20% of the Medicare-approved amount for some types of care.
Note that you don't get prescription coverage under Medicare, per se. You can purchase a drug plan.
Many don't really understand the complexities.