This might be long shot but a very promising long shot...
I work at a Transfer station in Melbournes South east on the weekends
the amount of useful stuff people through out in insane, so we collect all the usefull things and sell it funds going to the council ( bit of a fail there) but at least perfectly good things dont get burried in the ground.
Surprisingly alot of mobility aids get chucked, from deceased estates, taking up space....
this stuff is brought from someones garage in there car and chucked into a skip or placed on the side and collected by workers... so its not dirty or disgusting..
Worth a shot at your local transfer station. As alot of it is next to nothing in price..