With the economy down, most of us could use a drink right about now. The only problem is that spending $12 on a cocktail in a swanky Manhattan bar seems excessive, even in boom times.

So many New Yorkers are heading to where the drinks are free: the burgeoning open bar scene.

“Open bar is suddenly the coolest thing in the world,” said Seva Granik, one of the founders of Myopenbar.com, billed as “your guide to free booze.”

“There’s definitely more interest in spending less money,” Granik said, who noted the New York section of his four-year-old site gets about 2,500 to 3,000 hits per day.

Very Happy Hours

The good news for broke party animals is that there are plenty of free drinks to enjoy in New York. Various bars run promotional events where the free drinks flow in hopes of luring customers. Still, the tap is running dry at some joints where customers flee after the happiest of happy hours.

“I wouldn’t have come here if it wasn’t for the open bar,” Lisa Onderdonk, 21, said, sipping her free vodka cocktail at Highbar in Midtown. “I’m sure a lot of these people will stay.”

The open bars generally are sponsored by a specific liquor brand or paid for by the bar owners. Most take place in the early evening for a limited period to help draw crowds at off-hours. Some bars restrict drink choices – don’t expect always to pound down shots of top-shelf hooch for free.

“The catch is that it’s not every drink,” noted Steven Cobb, 21, a wardrobe stylist who frequents open bars.

Thirst for Profits

Some establishments are expanding open bar hours, encouraged by early success.

Last Spring, Crash Mansion on the Lower East Side experimented with running an open bar on Tuesdays in addition to a long-standing Friday night special. The open bars are organized in conjunction with live music shows, which has proven to be a successful combination.

“We get 150 to 300 people,” said Stephanie Adamo, a talent buyer for Crash Mansion. “These are definitely big draw nights.”

Despite the benefits of throwing open bar parties, things can also go wrong – at least from the organizer’s perspective.

“When the open bar finishes, the girls are gone,” said Rory Biscette, a promoter for Clubfix.net. “The guys will stay longer.”

Granik said there’s a risk people will just “roll in and drink the free booze” unless the bar offers an additional incentive for staying.

Mercury Bar in Murray Hill learned that lesson the hard way. The bar offered patrons free drinks on Thursday nights for three months, but didn’t get enough return business.

Ladies Night Rules

Darin Sergent, the bar’s general manager, said customers were just “downing drinks” and “double fisting.”

“We were really losing too much money,” he said. “It just seemed to backfire. It was very disappointing for us.”

However, Mercury Bar still run a Ladies Night promotion on Wednesdays from 8 to 9 p.m., when women get free Cosmopolitans, Martinis and well drinks.

“We are still getting a positive return on that,” said Sergent, adding that Ladies Night brings in the guys, who then buy drinks for the women after the promotion ends.