The alternative to Part D is a Medicare Supplement Plan, which is what we have (as an HMO with our medical provider's group). (I have to say that on the upside, THEY gave us no grief about immediately approving my knee replacement, whereas we had to force an appeal with our old insurance company, pre-Medicare.)
The Medicare Supplement HMO covered my Tdap shot without any hassles.
That said, they don't seem to like a med that I have taken for decades for tension headaches, so I may have to switch for something else for that.
As for antifungals being $$$$ expensive, yeah, tell me about it. I'm still battling that infection (which got out of control down in the hospital), and when I went to get a refill on one of the antifungal creams, the pharmacist told me that insurance wouldn't cover it because it would be "too soon". (Never mind the huge area that I have to cover, every day.) I asked the doc for a new prescription, got it, but so far as the pharmacy/insurance company was concerned, same thing - too soon, you can pay for it out of pocket, yada yada.
What REALLY burns me, is after talking to the pharmacist some more, was her "Well, this prescription will cost you (something like, I forget the exact amount) $545 if you pay for it out of pocket, but (reluctantly on her part, after I all but screeched at the cost) I can give you a coupon so it will only cost you $45..."
What The Bleep.
(Yes, we took the coupon.)