There are a few good stock simulators out there that do a pretty decent job reflecting what it's like to trade for real. Unfortunately they are just good, not excellent like I think they should be. Anyone interested in stock trading should have the best tools available to become as successful as someone that can afford a great stock trading platform from the beginning. However, as it is today, it's simply not available. The big boys still have the best and the fastest tools to trade and the little guy who is interested in making a little money in the stock market has to deal with these 'good' free simulators. But you have to start somewhere right. They do what they are designed to do and that is to educate you about the stock market. Fair enough.
The following stock simulators are all available for free on the web and require minimal sign up information to get started. They are listed in a random order.
The first one is from Market Watch called VSE or Virtual Stock Exchange. It's layout and community is pretty basic. If you have a facebook account you can connect to VSE right away and start trading. Also they don't allow trades under $2.00. So if you are trying to see if your penny stock strategy works, VSE is not for you. Overall it does work well though. I have an account with them for years and never had any major issues. On http://vse.marketwatch.com/
There is a lack of buy / sell stop and limit orders so you can only enter market orders, one of the things I don't recommend in real stock trading. Basically with a market order your order will be fulfilled whatever the market has to offer at that time. With a buy order this can be higher then what you originally had in mind to pay for the stock. Given the fact that the prices in virtual stock trading are always lagging minutes behind of the 'real' stock quote this can be a problem. Still, absolutely worth checking out, after all it's free. On www.weseed.com.
Last but not least, the sixth one called Umoo. I personally am not a big fan of them because they seem to reflect the stock market as a casino game. Sure, bets can be made in stocks, but only by the inexperienced. I believe with good analysis and research you can pick winning stocks consistently. They emphasize too much on the fun and play aspect of the stock market. Don't get me wrong, it can be a lot of fun to see your stock skyrocketing. But overall I think it's a serious component of our society where money can be made or lost. The good thing is that they have real money making opportunities in their games. Their contests allows you to 'win' real money without putting any of your own money in.
Overall the bottom line is to educate you and help you understand how the stock market works a little better. Go ahead and create an account with a few of them and see which one you like the best.