3D pen and 3D printer is very similar. 3D pen is smaller version and it have only 1 function. which is making by its own. 3D pen, you need to make it by own. you need to make every single thing by your own, and you need to stay on the 3Dpen while 3D printer just print automatically. so If you have more momey, please buy 3D printer. because if you buy 3D pen, there are not accurate, but 1 thing you earn with making things with 3D pen is you could become patient person.