That said, remember that sometimes you get what you pay for! The most economical company is not always the best online brokerage for your investing needs. There is frequently a trade-off in customer support and access to a wide variety of securities that accompanies ultra-cheap prices.

Ability to trade a wide variety of instruments
One of the best parts about investing online is the ease with which investors can put their money into not only stocks, but also commodities (such as gold and oil), bonds (such as Treasury bills), and a wide variety of other investment instruments. Make sure you select an online brokerage that will allow you to invest in all of the assets you are interested.

Let's take gold for example. Just ten years ago gold was selling at under $300 per ounce. Today it trades at $1,900 per ounce!. While in the past investing in gold was cumbersome due to the costs of physically transporting and storing the metal, today ETFs like GLD allow investors to quickly and easily invest in gold through their Online Brokerages Vs Traditional Brokerages: What Exactly Are The Differences Between These Brokerage Accounts?.