Contact churches in your area. They may have members or know of someone who needs one and can’t afford it. You can also call your local area Agency on Aging or Red Cross. Senior Centers May also know of someone. God bless you for doing this. I would LOVE if someone could donate one to us.
A veterans hospital/fraternal group? Or, a group that serves folks with diseases that would restrict their ability to use stairs --- MDA for example, ALS, MS.
We have an organization in our area "Foothill Caring Corps" that warehouses and lends medical equipment at no charge to the elderly. See if you can find such an organization in your area. Check with your county's Area Agency on Aging.
You can also call a local church, frequently they are aware of parishioners that need help.
Margaret