What To Look For
Backpackers who are still growing deserve their own top-of-the-line sleeping bag. If your young one often goes hiking and camping, keep in mind that they will eventually outgrow their bag. You may want to buy one that has a few extra inches of room so that they can get more than one season out of it. Look for all the things that a regular sleeping bag has, such as draft tubes to keep air from getting in at the zippers, mummy hood design if it's a 20-degree bag or colder and a boxed foot design for foot warmth and room. Water-resistant outer shell material is preferable. Companies such as Sierra Designs make youth sleeping bags with great features like an attached stuff sack so that it can't be lost. Small interior pockets are nice to have so that the kids can keep track of their headlamps.
Don't estimate the height of your child and guess that a sleeping bag you are ordering online will fit them. Know your child's exact height and purchase a sleeping bag with a length that is at least 6 inches longer. Many companies make only one youth size of about 5 feet long. The next size up in this case would be a woman's regular at about 5 and a half feet. Weight and stuff size matters if they will be carrying their bag on a hike. Down always packs smaller and is lighter but does not retain its warmth when wet. Rectangular sleeping bags that don't come with a stuff sack should be reserved for at-home sleepovers and not the backcountry.
Where To Buy
Purchase a youth sleeping bag from an online shop or catalog if you know the size you need. Sierratradingpost.com sometimes has great deals, Cabela's, Backcountry.com, Moosejaw.com, Campmor.com, Amazon.com and Trails.com all offer kids sleeping bags. Mountain Hardwear, Marmot, Kelty, Sierra Designs, The North Face and Eureka all make quality sleeping bags for kids. Shop at your local gear shop or store such as REI to try out sizes in person.
As mentioned before, kids will outgrow their bag eventually, so if you can find a bag that is on sale or even a slightly used bag, that is the way to buy. Luckily, kids' sleeping bags are less pricey than adult bags. They range in price from $30 to $140.