Mopac, I assume you are referring to the iCab app. I think that costs $50. The app for the FlyerChief engines is free as is the LCS app for iPads. Unfortunately, to run an S gauge Legacy engine in Legacy mode a 990 base is required. That is because all the data is stored on the Base. The controller can be an iPhone, but to pair an iPhone with a 990 base a Wireless LCS module is needed plus an LCS power supply and an interconnecting cable. Recall I commented that unlike in O gauge, S gauge Legacy engines do not have Bluetooth. If they did, none of the other stuff would be required.