No Such Thing as a Free Trade?

Some brokers think they've figured out a new way to grab market share in online trading -- giving away trades. Sound crazy? It might just be.

In the last month, two new free-trading sites have launched, while American Express(AXP Quote) has dished out free trades for more than six months.

But even if customers want to trade for free (and who wouldn't?), analysts question whether the concept works from a business point of view. ...