Residential brokers in the city have begun chopping thousands of dollars off of apartment prices on a weekly basis, hoping to bring in buyers by advertising how much cheaper the listing is than a month or a year ago. Prudential Douglas Elliman’s Darren Sukenik recently took over a listing of a 2,000-square-foot condo in Chelsea, which had been priced at $2.99 million. Within a week, he cut the price by $500,000. “It is a spectacularly designed, completely gut-renovated unit,” said Sukenik. “The problem was, it hasn’t been getting attention because it was entirely overpriced.” The apartment’s original price when it went on the market in 2007 was $4.2 million.