S.D.
The preschool that my children attend recommend a backpack that is large enough that you can easily fit a project in meaning the size of construction paper vary rarely they came home with something larger.My son had a normal 2 zipper compartment CARS backpack he used for 2 yrs in preschool.That was inexpensize less than $20.00 my daughter has a Dora bag found @ Walmart for $5.00 that is 1 zipper & is smaller than a reg. size backpack that is the perfect size for her.I personally wouldn't buy an expensive backpack for preschool or kindergarten because really they don't have a load to carry unless that'll be the only backpack they'll use for a few yrs.