A search for "iPod" on eBay yields a couple thousand listings for the digital music player and accessories, but beware: Hundreds of the listings are inducements to join pyramid-style scams.

Ebay is swamped with new "matrix" schemes, which appear to be legitimate buyers clubs but are in fact variations on classic pyramid scams, which are outlawed around the world.

In most cases, eBay shoppers are offered hot products like an iPod, a game console or a cell phone at an incredible discount, say for $40 or $25.

The eager bargain hunter is told not to bid on the item, but is directed instead to sites like My3Mobile, The Phone Matrix or Goraks.com, which offer iPods or cell phones as free gifts when products like CDs or eBooks are purchased.

The catch is that buyers only get their free iPod after more people sign up. When making a purchase, the buyer's name is added to a list. As new members join, names are shuffled up the list. When they reach the top, the iPod is dispatched

To speed up the process, buyers are often encouraged to recruit new members to join the scheme. And that's where all the eBay posts come from: Victims are using eBay to recruit new members.