I'm able to buy a bunch of laser and matrix printers but I'm not sure about the steppers inside. Does all laserprinters have steppers? I tried a deskjet once but that worked on a regular DC motor. Here's the list:
-Color Laserjet 4550
Star - LC-10
Is it worth to buy these printers for 100 euro? (it's everything or none...)
What do you want to use the steppers for? I would doubt that any of these printers will give you anything more powerful than a Nema 23 single stack which you could pick up new off ebay for about €15 each. If you want to make a CNC router for a dremel sure, but for anthing bigger than that, you will ant at least NEMA 23 double stacks.