You can replace the actual ev3 brick with a raspberryPi based BrickPi or PiStorms. Then a motor or sensor is about 30 bucks and you might have some lego technic

You can replace the actual ev3 brick with a raspberryPi based BrickPi or PiStorms. Then a motor or sensor is about 30 bucks and you might have some lego technic already lying around.