If you haven't much electronics knowledge/experience I think you would be advised to develop your skills first with a much simpler project.
Start by googling for tutorials on pcb making, soldering, stepper motor control and programming microcontrollers. Get those mastered first. You will also need good diy engineering skills.
As for cost, that could be anywhere from $tens to $thousands, depending on whether you source new or used components or build them yourself.