Hi there, if you haven't checked yet...you can go to the Medicare site to check on drug costs. Medicare has an excellent tool where you put in your drugs, and it tells you what the cost would be for various plans/pharmacies in your area. It is important to check each year, because drug plans change, and you may find a cheaper one for the following year.
I am checking now because I will need to start either OFEV or Pirfenidone (brand name is Esbriet). OFEV is a brand and has no generic so it costs more than generic Pirfenidone

Of course, I always warn people to get original Medicare (parts A, B, D) and do NOT buy a Medicare Advantage plan which will restrict the doctors you can see, charge you copays and require preapproval even for cancer treatments! And many places do not take those advantage plans. (Mayo for one).
Original Medicare allows you to self-refer to any doctor in the US that takes Medicare. You buy a Medigap plan to cover the 20% Medicare Part B(tests and visits) does not pay. Compare such plans on the Medicare site.
If a person makes the mistake of going with a Medicare Advantage plan and then wants to change back to original Medicare , they will have great difficulty finding a Medigap plan to cover the 20% Medicare does not cover. In the beginning all insurance companies have to accept you but not after the original enrollment period.