In addition to on-line sources, look for stores in your area that specialize in medical supplies, usually found listed under "durable medical equipment" or some such. The type of store that carries walkers, wheel-chairs, all the things that a disabled person may need. The ones in my area ALSO carry a wide variety of other consumable medical supplies at very very reasonable prices, like alcohol prep pads cheaper than even wally-world, and certainly much cheaper than any chain drug store. They also carry 4x4's etc etc. If they don't have it, I bet they can find it for you.
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"Better is the enemy of good enough."