Some shoppers turned Thanksgiving and Black Friday sales into a marathon event.
Despite the cold weather, many people headed to the Citadel Outlets in Commerce in search of the best deals.
Bargain hunters were also elbow-to-elbow at Westfield Santa Anita mall.
It's not only the deals that attracted customers at some shopping centers. To draw in Black Friday shoppers, the Irvine Spectrum Center in Orange County offered some entertainment, including holiday music and light displays.
People lined up long before sunrise to be the first ones in the door when Target opened Friday morning, snapping up televisions and other discounted merchandise.
More than a dozen major U.S. retailers stayed open for 24 hours or more on Thanksgiving Day through Black Friday, and crowds formed early.
Black Friday, the official start of the shopping season between Thanksgiving and Christmas, originally was named that because it was when retailers turned a profit, or moved out of the red and into the black. Retailers opened early and offered deep discounts.
But in the past few years, store chains have been opening on Thanksgiving.
Despite some resistance to the earlier hours, the National Retail Federation said 140 million people planned to shop during the four-day holiday weekend.
The shopping frenzy got out of hand at some stores across the U.S. as customers fought for bargains.
Two people were taken into custody after police say they attacked a man as he left a Wal-Mart store in Rialto. Police said the victim and a friend were walking across the parking lot of the store on the 1600 block of South Riverside Avenue when they were confronted by two suspects who were in a vehicle.
One of the suspects, 25-year-old Raymond Rice of San Bernardino, got out of the vehicle and allegedly started punching and kicking the victim. Police said an innocent female bystander tried to intervene but she was also assaulted by the suspect.
Rice's relative, 31-year-old Chennel Smith of Fontana, got out of the car and allegedly started physically assaulting officers who were trying to break it up, according to police. Both suspects were taken into custody.
The man who was attacked was hospitalized, but has been released. One of the officers suffered a fractured right hand and finger during the incident.
Rialto police say there were also fights inside the store over merchandise. More than 5,000 people had lined up outside, but not everyone got in.
There were various reports of unruly crowds and arrests at stores across the U.S. on Thursday night. At a Wal-Mart store in Elkin, N.C., shoppers with TVs in hand had to fight their way through the crowds just to pay for them and get out the door.
The shopping frenzy also got out of hand in Beaumont, Texas, as customers fought for Black Friday bargains. Shoppers tried to get a hold of the last few 23-inch flat screen TVs advertised for $75.
Wal-Mart released a statement overnight saying that in spite of a few isolated incidents, things have gone smoothly at most of its 4,000 stores.
The Associated Press contributed to this report.