What is the best kids' sleeping bag to buy if I'm only buying one?

The REI Kindercone 20 is the one. It earns its price tag across multiple seasons — the mummy shape keeps them warm without being claustrophobic, and the temperature rating is genuine enough for actual camping, not just backyard sleepovers. It’s the kind of gear you buy once and forget about, which is exactly what you want from a bag they’re going to drag through dirt, tent floors, and the occasional spilled juice box.