The Monday after Thanksgiving, tagged "Cyber Monday" by the National Retail Federation, marks the first big online shopping surge for many merchants as consumers return to their work computers.

A number of retailers are hosting one-day sales or special offers for the occasion. Internet research firm comScore Inc. estimated online sales may exceed $700 million online on Monday.

As for brick-and-mortar outlets, ShopperTrak RCT Corp., which tracks total sales at more than 50,000 retail outlets, reported late Sunday that sales on Friday and Saturday combined rose 7.2 percent to $16.4 billion from the same two-day period a year ago.

The biggest draw was electronics, benefiting chains like Best Buy Co. and discounters such as Wal-Mart Stores Inc. and Target Corp. Popular-priced department stores including J.C. Penney Co. and Kohl's Corp. drew in crowds with good deals.

Toy stores like Toys "R" Us Inc. fared well too. Still, apparel sales appeared to be mixed at mall-based clothing stores, though a cold weather snap helped spur sales of outerwear and other winter-related items.

"This was a really good start," said Bill Martin, co-founder of ShopperTrak. "There seemed to be a lot of pent-up demand."

Now the attention moves online. Toys "R" Us Inc. will hold a one-day online sale and rival eToys.com will launch a two-day sale. Wal-Mart Stores Inc. will begin five days of online-only sales.

Online jeweler Blue Nile Inc. will give customers 20 percent off purchases paid through PayPal, eBay Inc.'s electronic payment division. Target Corp., Circuit City Stores Inc., Sears Holdings Corp., Crate & Barrel, the Discovery Store and Overstock.com Inc. are among dozens of retailers offering free shipping that day.

"The online community is getting more competitive as the amount of new customers slows," according to Scott Silverman, executive director of Shop.org, an online arm of the National Retail Federation. "Add to that the concerns about the economy, and promotions and sales provide a great way to get people excited."

Silverman said the number of retailers offering free shipping with no conditions, such as a minimum purchase, has jumped to 41.4 percent from 36 percent last year.

Nearly one-third of retailers are also having special one-day sales for Cyber Monday. Forty-two percent plan some kind of promotion, according to the NRF's annual survey.

In fact, the number of retailers hosting online deals on the Monday after Thanksgiving has surged to 72 percent of those polled from 42 percent just two years ago.

Despite a decent showing, many shoppers interviewed said they planned to curb their spending. Earl Lee, a mechanic from Live Oak, Fla., who was shopping in Tallahassee, said that he was planning on spending less this holiday season.

"Gas prices, everything's so high," he added.

John Muller, of Clifton, N.J., who was standing outside Macy's Herald Square in Manhattan on Sunday, said he plans to spend only about $500 this year, half as much as a year ago, because of higher expenses and worries about the economy.