As a parent i bought my son (14 years old) an airsoft gun. I made sure it was one of the lower velocity guns (200-300 fps) and I made sure he understood proper safety procedures, mainly proper eye protection. I know for a fact that a rock from a slingshot would do more damage than an airsoft gun. It is really a pretty safe activity if done properly.

Haha..

My dad wouldn't get me a paintball gun..

But he would get me a 5$ hunting slingshot.

Find a good rock, fire..Can't find the darn rock after it rebounds off something, god knows how far it goes.