Ace Teah via Amazon offers the Ace Teah Waterproof Dog Seat Cover in Black for $28.99. Coupon code "OASOAHES" cuts it to $19.99. With free shipping, that's $9 off and the lowest price we could find. It features side flaps, nonslip backing, and quick release clips. Deal ends August 13.

Update: The price has dropped to $19.99. The coupon no longer applies.