eBay has the All In Motion? Faux Neoprene 17" Backpack (Sage Green) for $14 with free shipping.

eBay has the PUMA Eclipse Kids' 18.5" Backpack (Gray/Black/Floral) for $16 - 30% off in cart = $11 with free shipping.

Amazon has the adidas Team Issue II Medium Duffel Bag (select colors) for $22 with free shipping on $35+ or with Prime. Features 6.5" shoulder drop and made of durable woven fabric with a water-resistant base, it has a spacious main compartment and a ventilated side pocket for wet or muddy shoes, a padded shoulder strap and padded handles make for comfortable carrying.

Has excellent Amazon Reviews.

Amazon has the Amazon Basics Wear-Resistant Base Large Tool Bag (TB002) for $16 with free shipping on $35+ or with Prime. List price: $24. Features 15.9"L x 8.3"W x 9.1"H, Removable shoulder strap, 100% Polyester.

Has excellent Amazon Reviews.

Amazon has the adidas Excel 2 Insulated Lunch Bag (977438) for $16 with free shipping on $35+ or with Prime. List price: $32. This adidas lunch bag is insulated for temperature control and has a mesh pocket inside that can hold an ice pack. the lining is easy to wipe clean with soap and water.

Has excellent Amazon Reviews.