One of THE most important investment decisions you will ever make is your choice of broker. There are now more than one hundred companies offering brokerage on the Internet. However, look closely at what the company's advertised rate really applies to. In the majority of cases there will be higher brokerage for limit orders, options and those using a 'live' broker on the phone. You may find that the advertised commission rate may hardly ever apply to the types of trade you do.
Many companies charge extra 'hidden' fees which can add significant costs to each trade.
Very naughty, as it makes that cheap commission rate not so good after all. You really need to look at the company's fine print or e-mail them for more details. Most charge a significant premium over stocks. Most firms also have high extra rates if you want to place a trade over the phone using a 'live' broker. Beware high minimum balances required to open an account.