As for hardware, consider picking up a cheap vinyl cutter. Most of them are knockoffs of the Roland CAMM series, which itself is a beefed-up knockoff of the early HP pen plotters. As a result, they all speak HPGL, and most of the blade holders are basically modified pen holders. You can put a pen in a vinyl cutter, and most of them include a pen holder by default, as a way of testing the machine without wasting vinyl.

Vinyl cutters are optimized for slower motion with more stiffness and torque, whereas pen plotters expect nearly zero force on the tip and are optimized for speed and acceleration, but if you're not running production, speed won't matter so much. Vinyl cutters also have controllable downforce (by regulating the current in a solenoid), which can be neat.

My local makerspace has a USCutter MH-series, which is available in a cute little desktop size, or with a sensible stand for the larger models. Contrast with most of the genuine-vintage plotters that are weirdly bulky and awkward, not built to come apart for transport, and have 40-year-old power supplies lurking inside just waiting to blow up.