Ameritrade (AMTD) - Get Report has quietly unveiled an online brokerage arm that offers the cheapest of cheap online trades -- free ones.

Freetrade.com

is offering qualified investors free online trades for market orders, or trades at the market price. Limit orders, in which the investor can set the price, cost $5 each.

But, for nothing, investors get very little besides their trades. In a press release posted on Freetrade.com, the company says, "This will be a completely virtual company. This company will not use telephones or any type of mail service (except to collect signatures prior to a digitized system)."

Furthermore, for now it won't offer short-selling (a technique used that bets stocks will fall), options trading, mutual funds, bonds, bulletin-board stock trading or extended-hours trading.

Ameritrade expects to make money from Freetrade.com through advertising, interest income on customer accounts, and payment for order flow -- getting paid for sending trades to other brokers -- according to the press release.

Traders will have to meet special requirements, the company says. "For example, the investor will need to demonstrate experience with a discount broker and experience on the Internet," the press release says.

Ameritrade already was one of the cheapest online brokers, charging $8 for a market order. Commissions were once a hot topic among online brokers, but recently they have battled each other more on new services, such as access to initial public offerings.

Yet there still was a customer group made up of very active traders who wanted low commissions. And since their volume often makes up for the low commissions they pay, online brokers recently have been trying to cater to this group.

But

The New York Times

, which reported on the venture Saturday, noted that Ameritrade risks taking customers away from its flagship site with the new brand.