Under the Medicare Part A and Part B Medicare incontinence products and incontinence supplies are not covered under those Part A and Part B original Medicare plans.
However if you or someone has supplemental Medicare then some incontinence supplies or incontinence products are covered under Medicare supplemental plans.
If you cannot afford to purchase the incontinence supplies such as pads, adult diapers etc then you can look into NHS or Medicaid.
Medicaid covers incontinence supplies including, incontinence pads, adult diapers etc in most states.
However they usually only pay for adult diapers that are very low quality and may leak on you so it may be best to go online and purchase the adult diapers yourself to get quality adult diapers.
Also to note that Medicaid is a state-run health benefits program, so benefits will vary by state.