SteepandCheap offers the Patagonia Nine Trails 15-Liter Backpack in Navy Blue for $39.50 plus $6.31 for shipping. That's the lowest price we could find by $17, although most retailers charge $79 or more. Features include weather-resistant nylon construction, a hydration compatible design, folding top load and zippered main compartment, two front pockets, foam back panel, air flow mesh vest-style shoulder straps, and compression straps. It's available in sizes S/M and L/XL.