Staples offers the Jansport Vector Accessory Pouch in Black for $6.39. Opt for in-store pickup to avoid the $9.95 shipping charge. That's the lowest price we could find by $10. It measures 3" x 7.5" x 2.5".
eBags via eBay offers this Traveler's Choice Rome 20" Hardside Rolling Carry-On in several colors (Gray pictured) for $39.99 with free shipping. That's the lowest total price we could find by $6. It features a telescoping handle, tie-down straps, and internal pocket. It measures 21" x 15" x 9".