For forex- you can sign up for a demo with Forex.com or many other various forex sites. It's very easy to sign up for a demo from my experience.
ThinkorSwim onDemand trading lets you pick any day and time in the past 5+ years and trade it as it happened. Great tool to test your day trading strategies in a simulation environment with actual quotes and prices as they occured.
You cannot use the OnDemand Function for live data unless you have an account with TD Ameritrade. It doesn't take much to open an account with them. However, if you do not want to open an account with them you can play back previous days. Plus current day feed is delayed by 15 minutes.
Check out these guys, Cannon Trading. They have a lot of the different platforms for you to play with. Most of their demos are 14 days trial, but if you call or email them, they will extended. https://www.cannontrading.com/software/help-me-choose-the-best-futures-trading-platform I been playing with their ninjatrader with zenfire Hope that helps and good luck.
NinjaTrader is fully functional and free to use for simulated trading. You do need data. The following page outlines one's options. http://www.ninjatrader.com/DLP
I've literally just jumped into learning option and I started with the virtual platform on CBOE.com. It doesn't cost and it also offers free interactive tutorials. I took my very basic options knowledge and have been able to execute "profitable" moves. Good luck! http://www.cboe.com/tradtool/virtualtrade.aspx