There are two routes for Medicare and with both ways you will pay the US Government Medicare Part B premium which is $170.10 in 2022. If you are high income you will also pay an Income Related Monthly Adjustment Amount (IRMAA) and here is a link to the official table Part B costs | Medicare.
If you take the Medicare Supplement route and the recommended Plan G the age 65 premium will be about $120 a month depending on Aetna, BlueCross, Humana, UHC, etc. With the Supplement route you will also pay for a Prescription Drug Plan from a low of less than $10 a month to $50 or more. Unless you have the IRMAA mentioned above your monthly premiums will total around $300 to $340 ($170.10 + $120 + $10 to $50). Nearly all eligible medical expenses will be covered 100% with the exception of some prescription costs and a one time annual deductible of $233. The advantage of Supplement is nationwide providers and medical treatment freedom.
If you take the Medicare Advantage route most plans have zero premiums. You will still pay the US Government $170.10 for Part B plus any IRMAA. However here you will have copays, deductibles, and coinsurance. The zero premium plans are predominantly HMOs from Aetna, BlueCross, Humana, UHC, etc. and the HMO will direct all of your healthcare. There are a few PPO Advantage plans with low monthly premiums of less than $90 and lesser benefits. The PPOs provide the freedom of nationwide provider networks and not needing a primary care physician to direct your care. Many Medicare Advantage plans have extra benefits which may include various levels of dental, vision, home visits, transportation, and more.