Groupon offers the Geigerrig Rig 1200 Hydration Backpack in Black/Blue for $84.99 with free shipping. That's the lowest total price we could find by $55. It measures 20" x 12" x 6" and features ballistic rip-stop nylon construction, 100-oz. reservoir, heavy-gauge zippers, Apple iPod pocket, external bungee storage, and external mesh pockets.