Wolfyok via Amazon offers its Wolfyok 20-Liter and 10-Liter Roll-Top Duffel Dry Bag 2-Pack in Blue/Yellow for $22.99. Coupon code "ZH8PXLDH" drops it to $17.93. Plus, Prime members bag free shipping. That's tied with our mention from two weeks ago, $22 off, and the lowest price we could find. (For further comparison, we saw just the 20-liter bag for $13 in June.) These waterproof PVC bags feature removable, adjustable shoulder straps (one strap for the 10-liter, two for the 20-liter). Deal ends August 31.