My spouse and I continued fed health ins, but did not join Medicare part B. Late enrollment cost now?

Part D is for prescriptions so that may be the problem. Part B is more for doctors and some aids. I don't think there's a penalty for signing up for Part D late, but you usually have to do that during open enrollment which starts in November for 2016.

Please update us when you can.
Carol

If either of you were still working past age 65 AND covered by group insurance until now, I don't believe you pay a penalty. Or they would deduct the penalty for the years you had other creditable coverage.

It's a little more complex than it may seem. My husband waited 11 years to sign up for Part B. This was because he took NO MEDS for all this time. He suddenly found himself taking 3 meds/month. I called in to one of the servers to check it out and found that he would pay $34 more per month. (his social security check is very small). The kicker was that if you signed up for a specific 3-month mail order only insurance he would pay only -- 0 -- yes, that's free for his meds. So be sure to call and ask what is available for your situation. They were very helpful.

There will likely be a late enrollment fee. The reason they do that is that they don't want people to wait until they are sick before they enroll. I can't tell you the fee but you can likely find out on the Medicare site at medicare.gov or at least you'll be directed to information. Signing up for Mymedicare is helpful.
Take care,
Carol

You will pay 10% more for each year you did not enroll after age 65. This will go on forever. It isn't a one time late fee. So if you're 75, and you haven't paid for 10 years, that's about $100 a month more for each of you. I did the calculations, and if you live to an old age, you don't save anything by not enrolling in Part B at age 65. In fact, you will spend a lot more over the rest of your life.