Actually it's my local prosthetist at the hospital. They don't just make prostheses: they make braces and custom footwear also.
And I don't mind sharing how much I paid for them: zero π Where I live in Europe, healthcare is free, and these shoes were graciously granted to me by the public hospital as a prescription.
And because public money paid for them - i.e. the community - I'm very grateful and I intend to take very good care of them, to avoid having to change them for as long as possible. But if / when I need a new pair, all I have to do is call the hospital and they'll make me another one for free until I die.
I did inquire about the price if I wanted to order a pair like this on my own money, and while they were reluctant to say, I deduce that they run north of 3000 euros. And they're not turning a profit on them.