Uno, Motor Shield and Stepper Motors - required voltage and amperage

Well all you need to get started is:

Arduino Uno
stepper driver like TMC2209
Nema17 stepper motor
breadboard
12V PSU

and a tutorial like

A lot of DIY 3d printers were based around similar technology, so it is quite easy to find suitable h/w. I have a whole bunch of stuff from old 3d printers.