The controller is only one of the elements needed to make the FRC-class robot function. Other options to consider that offer lower cost are ...
Use the simulator to challenge the programmers to navigate the field using sensors, build field-centric driver controls, etc.
Connect with an Arduino using the
toolkit. The code will run on the PC, but the Arduino I/O is used to learn about signals and circuits.
Use an NXT, FTC, or smaller robot system to learn about control, gearing, and game strategy.
None of these have the crowd-appeal of a T-shirt cannon, but they may well be a better investment for a rookie team.
Greg McKaskle