Makino via Amazon offers the Makino 22-liter Ultralight Foldable Backpack with Blanket in several colors (Green pictured) for $16.99. Coupon code "PVSFH5XV"" cuts that to $10.19. Plus, Prime members bag free shipping. That's $7 off and the lowest price we could find. It features two side mesh pockets, 43" x 29" tear-resistant blanket, and two exterior zippered compartments.

Note: The same coupon drops the backpacks, without blankets, from $12.99 down to $7.79.