Answer:
I was just looking because our nearest public dialysis machine is more than 100km away...
They are not expensive, an auction site i googled starts them at $89 and I saw one for $500, I'm sure you can also pay a lot more for them too of course.
There are also new portable machines coming out now, some are only ~5kg (10lb) and can be worn on a belt, they give more gradual dialysis over a longer time rather than a short intense treatment.