Free trades are gone, but some commissions are still cheap

— -- Q: What is now the most cost-effective way to buy or sell a single share of stock or even just a few hundred shares?

A:Whenever the stock market and economy struggles, it doesn't take long before you start to see some of the best deals offered by brokerage firms go away.

And that has happened, again. For years, my suggestion for investors just looking to buy or sell a share of stock was Zecco.com. The online brokerage offered free commissions, making it an ideal way for investors who wanted to experiment buying or selling stock to try it out for no cost. And even for investors hoping to sell a few hundred shares of stock at a low cost, Zecco was a great option.

However, Zecco this year limited its zero commission offer to investors that meet certain requirements, including those with account balances of $25,000 or more. To get free commissions, you'll need to have an account balance of at least $25,000 each month for at least one day.

If you're able to maintain that kind of a balance, then Zecco certainly deserves your attention. After all, free is hard to argue with. However, if you do have a $25,000 or higher balance, you should also look into the free-commission offers from both Wells Fargo and Bank America, available to investors with balances of $25,000 or more.

But what if you don't have $25,000 sitting around to put into a brokerage account? Well, while it's not free anymore, Zecco's commissions aren't too shabby at $4.50 a trade. In addition, Zecco offers a money-market sweep account, that will move any cash that hasn't been invested into a money market, if you choose.

But if you're going to pay $4.50, it now pays to examine a few of your other alternatives, too. TradeKing, for instance, charges $5 a trade. For the extra 50 cents, you get access to a robust brokerage website, that also lets you buy and sell fixed-income, something of great interest lately. TradeKing also offers data and education on options investing. However, TradeKing currently does not provide any compelling place for you to park cash that's not invested.

Sharebuilder.com charges $4 a trade, as long as you're willing to wait a week or so for your order to fill. Sharebuilder is also linked with ING Direct, which offers an FDIC-insured high-yield savings account. If you want to primarily put your money in a savings account, and periodically dabble with investing, it's an interesting package.

Matt Krantz is a financial markets reporter at USA TODAY and author of Investing Online for Dummies. He answers a different reader question every weekday in his Ask Matt column at money.usatoday.com. To submit a question, e-mail Matt at mkrantz@usatoday.com. Click here to see previous Ask Matt columns.