This is quite the appealing one-bedroom, one-bathroom apartment, located on the first floor of the Harlem cooperative 1919 Madison Avenue. And it’s asking $512,000, a reasonable price for NYC real estate. There is, however, a catch behind that asking price. This is an HDFC apartment, meaning that to qualify to buy it you may need to make less—rather than more—money. (Such tight income restrictions have kept hundreds of HDFCs empty around the city.) Still, the apartment value has seen a boost in recent years, as it last sold in 2013 for $140,000.