I know this area. The houses are Drogan-style 60s modernist tract houses. The pictures show clearly that the house was totally remodeled but not torn down. The walls and ceilings and room layout are all original but refinished or resurfaced. My guess is they spent at most $100 per sqft, i.e. $200K, on the remodel. It could have been only $100K if they were economical. The new windows for example look like vinyl, not high-end wood.