The day after Christmas is the third biggest shopping day of the year.
After Christmas shopping is expected to make up about 10 percent of holiday sales.
Millions of people across the country stormed the malls on Monday for those Mega Monday sales.
On Tuesday, retailers will be adding up those receipts. They're hoping the $469 billion holiday shopping bonanza is a sign of a weak economy getting back on the road to good health.
"It will definitely be a good sign if consumers are out there this shopping season. People are feeling good and out shopping," said Lori Wachs, the founder of Cross Ledge Investments.
Post holiday sales are stronger than retail analysts expected. With deeper discounts of 50 to 80 percent, they're hoping this week will be the gift that keeps on giving.
"If they waited for the day after Christmas, they would get some really terrific deals," Wachs said.
"We got really good deals. Everything was very well-priced.It was probably close to 90 percent off the sticker price," said Bonnie Leviere, a shopper.
Unfortunately, not everyone was out to shop on mega Monday. It was also a day of many unhappy returns.
"What's the worst thing you got for Christmas?" a reporter asked a group of shoppers.
"Ugly clothes," some people replied.
One shopper even showed an example.
"What is it?" the reporter asked.
"Some really ugly outfit," the shopper replied.
Shoppers are expected to return some $47 billion worth of gifts this year, up more than four percent from this time last year.
"There were some things that didn't fit. There's obviously some good deals too," one shopper said.
Those unwanted gifts are sometime too much trouble for stores to restock. So they're packaged up and sent in bulk to discount retailers like TJ Maxx, Marshalls and Ross, meaning some of the best bargains may still be weeks away.
"Some stores give you a hard time if you don't have a receipt," one shopper noted.
Shoppers returning items should be prepared to show an ID. Retailers like Best Buy and Target have cancelled their re-stocking fee. But they're checking IDs and tracking returns to prevent fraud.