(REUTERS) - Online shoppers spent more than half a billion dollars on Cyber Monday, according to Adobe. The company expects that number to grow to US$3.36 billion (S$4.8 billion).

Top-selling electronics include Sony PS4, Microsoft Xbox, and Samsung 4K TVs. In the toy department, Lego had a major lead, with Nerf, Shopkins, and Barbie trailing right behind.

But shoppers don't have to wait for Cyber Monday to get good deals online any more. Retailers offer a lot of online discounts all year long, and deepen them around holiday season, even before Black Friday. Millennials play major part in it, says Adobe's Tamara Gaffney.

"Millennials, actually, believe that Black Friday has lower prices than Cyber Monday. It's not really true in all categories, but in some it's true. But, also, they just really, really like to be online, and they're very comfortable with mobile shopping," said Ms Gaffney.

Mobile shopping accounted for US$205 million.

Shoppers have spent US$36.5 billion online so far this year, according to Adobe. That's up more than seven per cent year-over-year.

And it's a growing trend. Another company that tracks the retail sector, IBM, said that, in the weeks leading up to the holiday weekend, online shopping was up nearly ten per cent from a year ago.