Amazon with best--deals has the Unigear Waterproof Floating Dry Bag (2L) for $9.99 - 25% off coupon (check "Apply coupon" box) - $2 off with coupon code K463F7TM [Exp 5/24] = $5.49 with free shipping on $25+ or with Prime. Same code works on the other sizes (prices after code range from $6 to $19 for up to 40L size).