if you use it to view forex, real time date is free forever (for 3 days data), create a connection and thro' Gain Capital's demo account.......
You can get free license after registration in website. You only need to pay if you need to place order from it to your real IB account.
besides its free to veiw forex charting from Gain Capital and ES/YM contracts from Zenfire, you can download (free of charge) many useful technical indicators to form trading strategies, like VMA, Market Profile etc. Go to the ninjatrader's support forum.....