Thanks to the Gods of Good Fortune, Girl Boss says Carrie only paid $700 a month for her Upper East Side, rent-controlled space, which the New York Daily News says would have cost $1,709 in 2000 (or about the time season 3 went to air, according to IMDb). Today, the Manhattan Rental Market Report shows the average, non-doorman apartment rental fee clocks in at about $2,160 a month for a studio, and just over $2,700 a month for a one-bedroom. 

If Carrie's apartment was actually a two-bedroom that became a one-bedroom because the spare was turned into a walk-in closet, she'd be looking to pay just under $3,500 today. And if, as Girl Boss estimated in 2018, Carrie's sole income came from her column (which happened in season 1), she'd be making $4,333 a month. After utilities and food, there wouldn't be much left to pay for cosmopolitans, let alone the latest Manolos or a new Fendi Baguette.