Deep discounts and extended holiday hours drew big crowds to shopping malls this year.? And with Christmas falling on a Sunday, shoppers were back in number for what retailers called "Mega Monday".

Experienced shoppers say it's the best time of the year for bargain hunters. "Yeah, I usually shop the last or the day after Christmas because that's when I can get all the bargains and a lot of the things I get, I can save for next year," one woman said.

The National Retail Federation projects a 3.8 percent increase in holiday sales -- up a full percentage point from its orginal forecast.

Retail analyst Lori Wachs says that amounts to a $469 billion shot in the arm for the U.S. economy.

"People are feeling good and out shopping and that should start to bode well for things to come," Wachs said.

Retail experts say shoppers can expect to see hefty discounts for the rest of the year as retailers clear their inventories. The National Retail Federation's Mike Gatti says the week after Christmas typically accounts for about 10 percent of holiday sales.

"That's always a great time for shoppers to get out and get terrific bargains as well," Gatti said.

But the week after Christmas is also prime time for merchandise returns, an estimated $47 billion this year.

Consumers can also expect longer lines at some stores as customers redeem millions of dollars in gift cards. ?

Those wishing to avoid big crowds are increasingly turning to the Internet. Retailers say online sales are up more than 16 percent with a growing number of shoppers making purchases this year using their smartphones.