EasyLunchboxes 3-compartment Bento Lunch Box Containers (Set of 4) for $13.95.  Shipping is free on orders over $25.  If needed, use this Filler Tool to pad the order for free shipping.  Here is a screenshot for your reference.  It is meant to be kid-friendly, and has 3-compartments.  It contains no BPA, PVC, or phthalates.