I bought a copy of the current issue of Homes Kenya Magazine. There is a story there that Mabati Rolling Mills (NRM) are to start selling prefabricated houses. Specifically, it says a ready-made steel house will retail at 80k for a two and 160k for four-room homes respectively.
I will do a followup on this and post my findings right here.
Most likely the above cost might not be including the foundation.
"..I am because we are. "― Ubuntu, Umtu,