Forget day trading — the best way to make a buck this holiday season may be to flip your Xbox 360.

Some people fortunate enough to get their hands on Microsoft Corp.'s new video-game console when it was released Tuesday immediately resold them on eBay, occasionally fetching thousands of dollars for packages that sometimes also included games and other add-ins.

The online auction site said about 1,800 Xbox 360s were sold there between midnight and noon Pacific time Tuesday.

Retailers across the country had opened their doors at midnight so gaming enthusiasts — and, apparently, entrepreneurial eBay users — could get their hands on the console immediately after it came out.

Internet retailer Amazon.com Inc. and the Web sites for Circuit City Stores Inc., Best Buy Co. and Wal-Mart Stores Inc. all listed the consoles as being sold out Tuesday. Best Buy spokesman Jay Musolf said the company also sold out of the consoles at most of its brick-and-mortar stores Tuesday.

EBay said the average price for consoles, including those sold with games and other add-ons, was $660. However, the company said some console packages were selling for as much as $2,500, with bidding and sales prices varying widely.

The North American retail price for the consoles is $399.99, while a slimmed-down version without a detachable hard drive and wireless controller sells in stores for $299.99. Some retailers were offering packages including games and other add-ons for hundreds of dollars more, however.

Hani Durzy, a spokesman for San Jose, Calif.-based eBay Inc., said the company couldn't compare the amount of Xbox 360s being sold, and the premium users were willing to pay, to previous videogame console releases. That's because the company only recently began using technology to track sales in such a detailed way.

But in general, he said he wasn't surprised by the frenzy, calling it "par for the course" whenever a hot new electronics item is released in limited numbers.

"What you see on eBay is a classic reflection of supply and demand," he said.

Microsoft has said it plans to sell 3 million of the new Xbox 360 consoles worldwide within 90 days of its launch.

The Redmond company has said it is producing Xboxes as fast as it can, and that there aren't any production problems.

Some retailers have said they expect to be able to restock their shelves weekly between now and the holidays, although most won't divulge how many consoles they will get each week for competitive reasons.

Still, Microsoft has conceded that an ambitious plan to launch the console worldwide within a few weeks — rather than staggering releases over months and months, as is typical — will mean fewer consoles initially in North America.