Having had two wonderful kids go through Cub Scouts, Boy Scouts, and Girl Scouts, we started knife use at about the same age as your kids. We tried a LOT of knives to find the right one.

We finally settled on Kabar Dozier Spears.

The #1 think was it had to have a lock - and the Dozier locks are the typical kind.

It had to be low cost because we figured it would get lost soon enough (amazingly one ALMOST was lost, but both are still around) - the Dozier costs about $20.

It also had to be easy enough to open that the kids could open it. When they were younger they had to open the Doziers two-handed, but now that they're young teenagers they can open them one-handed using the thumb stud.