The #1 question people ask me is, "How much do I need to open an online brokerage account?". I always give people what I feel is a good answer. First, let me say that online brokerages have different minimums depending upon the firm you choose. Three of the more popular firms are TD Ameritrade, E*Trade, and Charles Schwab. TD Ameritrade has a $0 minimum to open a Brokerage Account. E*Trade has a minimum of $500 to open an account. Charles Schwab's minimum opening balance is $1000. So in theory, you can open an account with $0.
Opening and account with $0 will do you no good if you want to invest in a stock since the account is not funded. So that leads me to the next part of the question. "What is a good initial Deposit in your online brokerage account?" I answer that question with the answer of $2000. Here is why I say $2000 is a good starting point. You can somewhat diversify your funds. An example of that would be investing in 2 different securities in 2 different industries. Maybe you invest $1000 in one airline Stock and $1000 in one technology company. You have now successful eliminated some of the market risk of having all your eggs in one basket. Maybe you even take it a step further and pick 4 securities to invest in and spread out over 4 different industries with $500 in each to gain even more diversification.
If you have more than $2000 to invest, open the account with a larger amount. If you have less than $2000 open it with less. The important thing to remember is that continually adding to your account and creating some kind of savings plan will undoubtably help you save and grow your account faster. Everyone starts somewhere, so opening the account is step one. Remember, investing in stocks is a marathon, not a sprint!!!
The important thing to do is research a brokerage firm that you feel comfortable with and take that first major step of actually opening the account. Opening the account is the hardest part of investing because it requires you to get over the initial fear of becoming an investor. There is never a good time to start investing, you can always come up with something else to spend your money on. My advise is to take the money and get it into n account as soon as possible.