I'm on SSDI and have supplemental insurance. My supplemental is a regional HMO. I pay no premiums only co-pays and no deductibles. My prescriptions is also with them with no premiums, no deductible and 15% co-pay.

You really have to carefully read the part D prescription drug. I got screwed when the first implemented it. Medicare forced you to sign up and gave options on their website which showed premiums of $2/month which I picked. This plan premiums went immediately from $2 to $30 in a couple of months (now at over $60). Their deductible was $50 per transaction (my generic chemo meds cost $45/month), hence I never used them. I couldn't do anything about it since it was forced upon me by Medicare.

My solution was to stop paying. As a consequence, they drop me but Medicare is now saying I'll have to pay a penalty for the time I didn't have part D. But there is a program which will help pay for premiums and if I apply, don't have to pay this penalty. So, I'm applying for a program that helps pay for premiums which cost no money. Our government at work.