Something that money could be used for when it gets implemented is upgrading the KSC. For example, you would only start with a small VAB. From there you would have to buy a larger VAB to make bigger rockets, a dirt runway, upgraded to a paved runway, a launch pad, runway lights, a tracking station, etc. This would really help with the progression of the game since then not only are the ships evolving, but the space center as well.