Agree with you 4 room flat cost about $50K max included material and labour cost. But many not believe me ask I have said 4 room flat cost $40K without any renovation eg. flooring, light....
So HDB selling $300K that mean land value is $250K~$260K/unit with consider very expensive since now new HDB now is about 20 storey high which mean each plot land of 4 room flat size cost $250K*20= $5M for a land size about 900sqf. So that is how much gov. profit from selling HDB.
Enough to allow Daddy and butch-in-law to lose hundreds of billions overseas without batting an eye?