Online trading continues to utilize technology to increase the features offered by online brokerage firms, while also keeping costs low. These three discount brokers offer everything you need for successful investing while maintaining low per-trade pricing. If you are looking to leave behind the high fees of full-service brokerage firms, take a look at Charles Schwab, Fidelity, and TD Ameritrade to maintain a high service level at a fraction of the price. Charles Schwab has a minimum of $1,000 investment to open an account, $2,500 for Fidelity, and TD Ameritrade has no minimum requirements. All three of these brokers provide top customer service and are all a great option.