6 for $25, they are practically disposable. The Enerloops or IKEA AAA will cost more than the headlamp.
The only drawback is that they are H~~L, not L~~>H. They also have a pair of red leds, so kids will want to cycle modes.
There are also these, “for running, walking, fishing, hunting, hiking, cycling, reading, caving, auto repair & emergency kit or DIY as a waist lamp, Helmet Light, etc.”. I wanna see someone show up on the construction site sporting this:
Fenix makes some great kid headlamps, but they’re not a good fit. the HL05 is pricy at $15, and runs on 2xCR2032 (30 hours, but it adds up.).