You can either have an application form sent to you, or you can fill out the application on the broker's Web site, print it out, and mail it in with a check. The process is easy and can be done fairly quickly.

The minimum amount to open a new account varies, but it's usually in the $500 to $1,000 range.

All discount brokers are online brokers, but not all brokers that are online are discount brokers. Some brokers offer both stripped-down, frill-free services with low commissions, as well as full-service products with higher fees. Generally speaking, making a trade online is cheapest, touchtone phone trades are a little more expensive, and trading by talking to an actual person costs most.

If you're just beginning to invest, you'll probably opt for a discount broker. More and more full-service brokers have become reluctant to service individuals who have less than, say, $250,000 in assets.

Make sure you consider all expenses when choosing and using a broker For example, many firms charge maintenance fees if your account has a low balance.

There's a wealth of information on the Internet about brokers. Check out the sites of individual brokers, as well as sites that compare their services and prices, before you open an account. When you go to the site, find out what investment information and tools they offer for free. Play with the demos to make sure they make it easy to trade.

Market order. An order to buy or sell stock at the current market price. When you place a market order, you can't control the price at which your order will be filled.