I just signed up a couple weeks ago. If you or your wife are still working and have insurance you don't have to sign up for part B until you retire but you should sign up for part A. It's free and you can sign up on SS online in minutes. They ask the question do you are your wife currently have employer sponsored insurance click yes and it'll let you sign up for A only.

If a person is taking SS you're signed up automatically for A & B and it will come out of you check.

Supplements are different by location and cost are all over the place.