How do I get my mom's Depends for free?

I know what you mean. Look on eBay for sales.

Its hard to find them for free. Call around to healthcare agencies that do Hospice especially. Sometimes family members will donate supplies received during Hospice care.

From experience, I can tell you that unfortunately Medicare does not pay for incontinence supplies and either does supplemental insurance. I believe Medicaid does, but not Medicare. I’ve checked on Facebook Marketplace and found them on there for cheaper.