Under Armour has the Under Armour UA Undeniable Sackpack (Midnight Navy / Metallic Silver) for $14 - 50% off with coupon code CHEATCODE  and stacking 20% code EXTRA20 in cart = $7.58 with free shipping on $50+ orders or with ShopRunner.

Measures 19" x 15" x 2" with a side valuables pocket that's lined with soft tricot material.