As tax abatements on condo and co-op purchases dwindle, more New Yorkers are finding that the cheap monthly payments they were expecting aren’t a reality — for long. Douglas Heddings, a former senior vice president with Prudential Douglas Elliman and founder of the Heddings Property Group, told New York magazine that his client was wowed by an Upper West Side two-bedroom apartment, which had monthly taxes of just $600, thanks to a tax abatement. But this low fee won’t last long; once the tax abatement runs out in 2014, the fee will be $1,550 per month. While not exactly a bait and switch, this could be a nasty surprise for buyers who accept higher maintenance charges, for example, with the expectation that their taxes will remain low indefinitely. Nan Shipley, president of Rand Realty, said that reduced taxes incentivize buyers to purchase a pricier home, often with negative consequences. Many buyers will shop out of their price range because of these incentives, Shipley said, without considering the long-term costs.