I am sure Elwar paid more than that for his seastead.
I very much doubt it. I have been watching the whole process and they were admirably frugal right along. They used local labor, welded up the spar out in the open, not even in a shop. Dragged it around with whatever they could scrounge up.
Elwar is NOT profligate with his money, they shopped around for their little boat for some time, and ended up buying a fixxer upper.
I would be quite surprised if there was more than $120K into the prototype all inclusive.
If i recall, i think Elwar wrote somewhere that he and his girlfriend did not fund it, just agreed to live on it for a brief time. Also I think I remember him saying 130k was raised for it, but I dont know if that was all of it or just partial funding. My memory could be off on these and Im not sure if it was a WO post or an article.