Friday is "C" Day, the last day home buyers can sign sales agreements to qualify for the federal tax credits.

Eligible first-timers can get breaks of up to $8,000; the maximum is $6,500 for repeat buyers who have not bought a primary residence in five years or more.

As the clock ticked - Prudential Fox & Roach's Web site actually has a digital timepiece counting down the hours, minutes, and seconds to midnight - it was clear the push toward the deadline has been feverish.

"The last few weeks have been astounding," said Prudential Fox & Roach agent Jeff Block, and sales have been booming because buyers assume that the credits will not be renewed. "We advise our buyers to use the credit if they find the right home."

Builder Marshal Granor, a principal in Granor Price Homes, said the company's "Let's Make A Deal" weekends this month, scheduled to coincide with the credit deadline, boosted sales at its communities in Royersford and Bensalem.

"The concept worked," Granor said. "Of course, I would have liked to sell out entirely, but we created the buzz we wanted."

It's hard to quantify just how many buyers entered the market nationwide to take advantage of the credits.

Walt Molony, a spokesman for the National Association of Realtors in Washington, said: "Given the lag between contracts and closings, it's hard to pin a hard number on it, but we expect 900,000 first-time buyers and 1.5 million repeat buyers to qualify for the credit this year."

The Realtors group estimates two million first-time buyers qualified for the first tax credit, which expired Nov. 30.

Offering still more help to motivated buyers is the fact that mortgage rates have stabilized recently.

When, after a year, the Fed stopped buying mortgage-backed securities from Fannie Mae and Freddie Mac and investors returned to the secondary market, rates rose almost half a percentage point.

They are back to 5.06 percent, Freddie Mac reported. And as a result, the Mortgage Bankers Association said Wednesday, purchase applications rose 9 percent from a month ago.

Has there been a deadline rush for mortgage loans, too?

"That will likely happen after agreements of sale are signed and before the June 30 closing deadline," said Fred Glick, a Philadelphia mortgage broker who also sells real estate. "These buyers came in with preapprovals, so they'll start nailing down loans after contract signings."

"I have a couple of buyers who told me that it is more important for them to find the right house than get the credit," Glick said.

What is virtually certain as the government incentive winds down is that these tax credits will be the last.

"There will be no others," said Moody's Economy.com chief economist Mark Zandi. "Even the National Association of Realtors is not advocating an extension."

One reason, economists agree, is that the credits are costing the government billions in lost revenue and further deepening the deficit.

Qualified buyers who sign by midnight Friday and settle on the deal by June 30 - whether for a first-time or a repeat purchase - can claim the tax credit on either their 2010 returns or on amended 2009 returns.

In the first round of tax credits, new homes did not fare as well as previously owned dwellings. The recession has kept builders from putting up a lot of houses, so there was little inventory for ready sale.

Because it takes about six months to build a house from the date a contract is signed, buyers could not close in time. Add to that the fact that the typical new-home buyer has owned a house before - in the first go-round, only first-timers were eligible for a tax credit.

This time?

"The impact is definitely there," said South Jersey home builder Bruce Paparone, whose company signed two contracts Wednesday for move-in-ready homes.

Half of Paparone's sales will not be delivered until after the June 30 closing deadline, so those buyers will not benefit.

"But," he said, "they did sell their homes because of the tax credit, therefore benefiting us."

Contact real estate writer Alan J. Heavens at 215-854-2472 or aheavens@phillynews.com.