B&H Photo Video offers the Kata Large Sling Backpack
in Black, model no. KT DL-3N1-33, for $39.99
with free shipping
. That's $40 off list and the lowest total price we could find. It features three different carry options, 15.4" laptop compartment, tripod straps, two external zipper pockets, and can hold a DSLR camera with up to six lenses.