Mora clipper would be a good choice.
For a folder a Vic Huntsman is near perfect. All the necessary tools, not too thin not too thick.
For something slightly smaller try one of those Vic 84mm "My First Victorinox Plus"s or even the Vic 84 mm waiter. The "My First Victorinox Plus" has the rounded blade tip with no point, a combo canopener/bottleopener tool and a woodsaw. Also comes with a neck lanyard and a pocket chain.
My first Vic was a 84mm Recruit, thats a great little knife!
If you want to give them a "keep for a lifetime tough as nails SAK" then try an Alox Cadet II or and Alox Farmer.
Or if you must have a lockblade try a Vic Picknicker/Rucksak/Outrider. Although the 111mm frame may be a bit big for a kid.
For under 10 bucks you can get a carbon steel Opinel no.7. Its near perfect for small hands and the ring lock works well.
I like stainless AND carbon steel knives but maybe a carbon steel knife as a first knife is not a bad idea. It really doesn't hurt to show kids that yes there are actualy knives that aren't stainless and that they cut quite well thank you. lol.
