In the past few months, we have covered a bunch of whiteboard robots that can draw or write what you like. gocupi is a portable drawing robot for the Raspberry Pi. It relies on 2 stepper motors to control the position of the marker. This vertical plotter is controlled using a Pi 3 unit.
The kit comes with Nema 17 stepper motors, 2.5″ suction cups, a gocupi board, and a few other parts for you to get started. You can order yours for $300 at this time.