Retailers traditionally compete for shoppers' dollars on the Friday after Thanksgiving, known as Black Friday, with early hours and special deals.
This year, many are offering deals earlier and some stores, such as Sears and many Walmarts, will be open on Thanksgiving Day.
At Walmart stores, customers can bring in competitors ads and Walmart says it will match the price of any identical product at the register. The offer does not apply to online purchases.
Wal-Mart is also offering 150 online-only specials on Thanksgiving Day as well as "Black Friday" specials on electronics, clothing and home items in stores the rest of the weekend.
Shopper turnout for Black Friday sales will be a strong indicator of whether consumers will spend more this season in the face of economic uncertainty and high unemployment.
ShopperTrak, a research firm that tracks sales and traffic at more than 70,000 outlets, earlier this month raised its holiday growth forecast to 3.2 percent from 2.9 percent. That compares with a 0.4 percent decline in 2009, according to ShopperTrak's calculations.
