Cafago offers this 40-Liter Water Resistant Travel Backpack in several colors (Black pictured) for $17.49 with free shipping. That's $27 off list and the lowest price we could find. It features several pockets, alpenstock clasp, adjustable waist and chest strap, D-ring, survival whistle, and a breathable / padded back panel.

Note: This items ships from China and requires 18 to 28 business days for delivery.