B&H Photo Video offers the Samsonite Xenon 2 Laptop Backpack, model no. 49210-1041, for $45.99 with free shipping. Outside of the price below, that's the lowest total price we could find by $4. Features include a ballistic polyester exterior, brushed poly lining, adjustable padded laptop compartment for systems from 13" to 15.6", accordion-style storage design, and more.

A close price: Amazon has it for $46.67 with free shipping.