Brokerage commissions vary widely, depending on the firm and the customer. Commissions started falling in 1975, when they were essentially deregulated, and plummeted with the advent of online trading.

They typically range from $5 to $20 for an individual online stock trade at a discount broker to $150 for a typical trade done through a full-service firm.

The more assets you have at a firm, and the more often you trade, the lower your commissions are likely to be.

In late 2006, Bank of America started offering commission-free trades to customers who had $25,000 in assets at the bank. Several online firms have also started offering free trades.