Prices are still falling somewhat, but are now stabilising. A satisfactory MPC system currently costs somewhere in the region of £2,000 to £3,000, depending on the precise configuration. In theory, it would be possible to start with something less expensive than this, offering only some aspects of the full MPC functionality, with a view to later upgrading (as funds may permit); but, in the long run, this tends to be significantly more expensive, and also seriously compromises the immediate utility of the system for its intended users.
It seems unlikely that the prices of adequate MPC systems will fall very much further; instead there will probably continue to be a slow growth in the functionality of these systems, with the price remaining fairly constant.
£2,000 is a very substantial sum of money; notwithstanding that, I suggest that such a system should be affordable by many, if not most, schools, provided that its purchase can be financed over, say, several years. Interest rates are currently low, and attractive financing arrangements can therefore be offered.