TomTop offers the Cheng Xintu 55-Liter Water-Resistant Hiking Backpack in several colors (Royal pictured) for $19.99 with free shipping. That's $2 under our mention from two weeks ago and the lowest price we've seen. (It's the best deal now by $5.) It features a large main compartment with numerous smaller pouches, detachable internal aluminum frame, padded shoulder straps and back support, and adjustable chest and waist belts.