That is fantastic. I may have me daughter keep her eyes open on craigslist while I’m researching.
My brother just bought and installed a used one for my SIL.
His stairway has 2 different turns in it and he saved a small fortune by DIY. He ended up purchasing 2 different used models and mixed and matched to get the turns just right. The only challenge he has had after finding what he needed on Craigslist was the motorized chair thingy can occasionally throw an error. Keep in mind his chair is more complex than a straight one because the angle changes on turns and the chair needs to adjust to keep occupant in chair.
I wish for you good fortune on your quest! :-)