Amazon offers adidas Classic 3S 2.0 Sackpack, Twill Onix Grey/Black, One Size Fits All for + free shipping with Prime.

Product Description:
Keep your load light and your hands free. This adidas sackpack has plenty of space for the essentials, and cinches shut with a pull of the sturdy cords. Zip away your phone in the front pocket and you're ready to head out, travel cup in hand.