1SaleADay has this Logitech Bluetooth Aluminum Keyboard & Stand for Bluetooth Enabled Devices w/ 30′ Range & Shortcut Keys! for $9.99 (retail is $129.99).  While the case is designed to fit the Galaxy Tab 10.1″, the keyboard can be used with any Bluetooth Human Interface Device (HID) enabled device.
Coleman 38-Liter Backpack with 2-Liter Hydration Bladder in Black or Red retails for $99, but is selling here for $29.99.