Condo vs. rental
Take a look at the chart below, from Forest City Enterprises' Form 8-K, filed with the Securities and Exchange Commission on 11/3/15. It's notable how the one condominium building, 550 Vanderbilt, costs so much more than the rental units.
550 Vanderbilt will cost $361.5 million for 278 units, while the 100% affordable (albeit mostly middle-income) rental building 535 Carlton will cost less than half as much: $169.6 million for 298 units. The 38 Sixth Avenue rental building will cost $202.7 million for 303 units.
The B2 modular building, aka 461 Dean Street, will cost--after the latest cost increases--$192.1 million for 363 units, which will be 50% market, 30% middle-/moderate-income, and 20% low-income.