If it's just for ID purposes and you're SURE you won't want to sell it one day, buy an electric engraver. They're something like $25. They have a super-hard, pointed tip that vibrates and the length of stroke of the vibration can be adjusted with a dial.
It is very hard to get a professional looking result freehand though. I've never been able to do it.
If you buy the engraver, you won't save any money now, but if you engrave lots of stuff, it might be worth it. For example, my brother engraved all his tools with it.