It may not be such a great deal after all.

Groupon, the red-hot startup that offers subscribers daily deals through local merchants, has reportedly spurned a $6 billion takeover offer from Google in favor of staying independent.

Chicago-based Groupon may still decide to sell shares through an initial public offering but will hold off on a decision until 2011, according to the Chicago Tribune, which reported last night that the acquisition agreement was off.

After months of rumored talks, Google was believed to be on the verge of clinching a deal to buy Groupon for between $5 billion and $6 billion.

Despite the high price tag, Groupon would have fueled Google’s local advertising ambitions and helped fend off competition from social networking juggernaut Facebook, which just launched its own deal offering.

Groupon boasts a sizable sales force and relationships with mom-and-pop businesses in markets across the country. It sends subscribers daily e-mails offering them steep discounts on products and services ranging from restaurants to gym workouts — so long as enough people sign up for the offer.

A cross between Amazon and Facebook, Groupon has pioneered an unusual blend of online commerce and social networking that encourages friends to spread the word about daily deals.

Bargain-conscious consumers have propelled the company’s annual revenues to an estimated $500 million this year — a figure that could climb to $1.5 billion next year, according to estimates.

A sale to Google would have delivered a mega payday to Groupon’s venture-capital backers, including New Enterprise Associates, Accel Partners and Russia’s Digital Sky Technologies.