Ten year old boy needs a good knife. I'd like it to be something he really wants to take care of and keep, while at the same time recognizing that ten year olds don't always keep stuff. I think I'd like traditional styling, something in the 3" range so that he can actually hold it, and definitely a lock. $100 plus or minus $50 let's say.
A SAK is a thought. I always found them really hard to use. A good multitool is also kind of ok. Have to be American or European.