Black Friday has come and gone. Shoppers, get ready for Cyber Monday.

Online retailers came up with the idea of Cyber Monday – the first Monday after Thanksgiving – three years ago. It’s a time when online merchants offer big bargains for holiday shoppers and it’s the unofficial kickoff for the online retail season.

With the sluggish economy, many online retailers are planning to heavily promote Cyber Monday this year, with nearly 84 percent planning to offer a special promotion on Monday. According to the National Retail Foundation, that’s almost a 12 percent increase over last year.

Online merchants will be offering free shipping on virtually all orders, and many are also offering financing options such as no payments for 90 days and deals like $10 off a purchase of $50 or more, along with the normal discounts on products.

For example, Amazon.com will take up to 65 percent off watches Monday and offer one-day deals such as a $157 knife set for $49.99. Online auction site eBay.com is holding “the largest sale in its history” with $1 holiday door buster items hidden on the site that consumers must hunt for, such as a 65-inch Panasonic plasma HDTV and a 2009 Chevy Corvette.

Even with all the discounts and deals, it probably won’t be a banner year for Cyber Monday.

Consumer spending in 2008 has dropped so dramatically – down one percent in October, the largest drop since the terrorist attacks of 2001 – online retailers may experience a flat year after several years of vigorous growth.

“With the economic challenges arising this year, people are definitely spending less,” Jeff Wisot, vice president of marketing for Buy.com.