From my own professional experience: it costs a minimum of $350 per net rentable square foot for new construction of mid-rise rental apartment buildings. This includes all materials, labor and design/permitting costs, and the cost of land acquisition in the urban core of a second-tier U.S. real estate market (NC Triangle). $350,000, 1000-square-foot three-bedroom apartments are affordable housing. But good luck finding one in a new building!