to be fair, its been a while since i bought, so i went and checked prices and they were right where i remember them.
a real arduino uno board goes for $20-$25.
the kit includes "SOUND" Piezo & Sound Module and "LIGHT" Light Sensor Module, which im assuming are just a self contained piezzo buzzer, and a photo resistor.
i still didnt price a stepper motor, but again, a $20 arduino and maybe $20 worth of leds, resistors, and stuff, yeah, that still needs to be a $50 stepper motor to work out, unless that "sound" and "light" are a lot more special than they make them sound.
and au$ are not that far off of us$. all should be within 10%