Groupon offers the Cabin Max Metz Carry-On Backpack in 11 colors (Deutschland pictured) for $29.99 plus $3.99 for shipping. That's the lowest total price we could find by $1, although most stores charge $40 or more. It measures 21.6" x 15.75" x 7.9" and fits most carry-on regulations. It features a padded back, three external zipped compartments, and two internal zipped compartments.