The way of getting a cheaper Systema PTW is to get a Challenge Kit, which you will need to put together and already comes with all the pieces you need for a PTW. In this video Hyperdouraku puts together the Systema PTW Infinity Ultimate Challenge Kit with a test of their output at the end of the video... "This is a maintenance procedure for the SYSTEMA PTW INFINITY ULTIMATE CHALLENGE KIT, a state-of-the-art electric gun with a small brushless motor built into the gearbox.

This product is a toy that complies with the laws of Japan."