Every brokerage has different terms and conditions for opening an account.
Make sure you read the fine print beforehand, there is nothing more irritating that spending 2 hours filling out application forms only to find out you don't have enough to open an account. If you are a new or beginner investor you probably don't have pocketfuls of money to open a new account. It's a great way to invest for a few months while you build up the value of your portfolio until it's time to move to a real broker.