As long as you have Medicare Part B insurance the Medicare Part B will cover the cost of most diabetic supplies that a diabetic will need.
However the coverage for diabetic supplies coverage from Medicare Part B can vary so they may not cover the entire cost of all the diabetic supplies you may need.
With Medicare Part B coverage you may be able to get coverage for the cost of up to 100 test strips and lancets every month, and 1 lancet device every 6 months.
So Medicare does usually cover and pay for at least some diabetic supplies but usually not all and you're usually limited to the amount of diabetic supplies that they will pay for.
You can sometimes even go online and buy some of the diabetic supplies even cheaper such as through Healthykin which is where I buy my mom's test strips for really cheap for her.
I pay for them out of pocket for her because she can't get insurance to pay for them.
I don't mind paying for them as I can afford to buy them because the diabetic test strips are pretty cheap online compared to purchasing them in stores.