If you want to build your own plotter, but haven’t found a design that you can make with the tools at your disposal, this device by Mr Innovative is certainly worth a look. It uses an assembly of two steppers and lead screws arranged in an X/Y configuration, along with a hobby servo retract the pen’s ink tube/ball when needed.
Assembly, as seen in the video below, is accomplished with little more than a hot glue gun, drill, and saw. If you want to duplicate this yourself, you will, however, need to figure out a good way to physically hold the pen, as well as what type of salvaged or purchased stepper assemblies will work. Writing retraction is one of the more clever bits of this build, as a tiny string pulls the ink tube into the pen’s body through a hole in the side of the pen.
An Arduino Nano provides computing power for the machine, and L293D ICs control the two servos directly, all mounted to a custom PCB. More info on the build is found here, including a procedure for turning drawings into a format that this system can use via Inkscape and Processing. The resulting device likely won’t fit in the palm of a normal person’s hand, but is quite small and appears to do good work with simple drawings.