Raleigh, N.C. — The clock is ticking for first-time homebuyers wanting to cash in on a federal tax credit of up to $8,000.

The offer ends Nov. 30, and if you want to take advantage of it, you need to buy this month to go through the loan process and close.

"Right now, we're advising people to get in before Oct. 15 in order to meet that Nov. 30 deadline," said Carla Sevilla, vice president of sales for Pulte Homes.

Pulte Homes has seen demand spikes, putting putting sold signs on more than 100 homes in September, doubling its average monthly sales for the past 18 months.

Seventy percent of those sales are from first-time homebuyers.

"The tax credit is pushing people over the fence, I think," Sevilla said.

Loan consultant Christi Pittarelli says the reason for the Oct. 15 date is to make sure loan officers can verify employment, assets, income and to take care of other business so that the buyer can close on time.

The Internal Revenue Service considers a first-time homebuyer is someone who has not owned a home in the three years prior to purchase.

The tax credit is equal to 10 percent of the home's purchase up to a maximum of $8,000 and is available to single tax-payers making less than $75,000 or married couples with a combined income of less than $150,000.

Homebuyers must also live in the home for three years of pay back the tax credit .