Most of the boys in my Cub den carry, at my recommendation, a 10 dollar Victorinox SAK. My son has a Recruit, which is basically the standard Camp Knife/Scout knife configuration, deleting the awl in favor of a second, smaller knife blade. Others have those, and some have the Sportsman, which has a corkscrew on the back and a nail file instead of the second blade. Can opener, bottle opener, couple of screwdrivers. They are set. Those little knives are fine for anything a scout does. The standard Tinker, larger or small, would do as well, or the Super Tinker you can get at WalMart for under 20 bucks. If you just want a cutter for under 20 bucks, then get a Case Sodbuster Jr. in stainless or CV, at your preference.
Any of those would do whatever needs doing for anybody. They are well made, solid pocket cutters.