Viekoo via Amazon offers the Prooral Orthopedic Memory Foam Seat Cushion in Gray for $26.99. Coupon code "AR24DBOC" drops it to $15.92. With free shipping, that's $4 under last week's mention, $11 off, and the lowest price we've seen. It measures 17.7" x 14" x 2.8" and features a washable cover with nonslip rubber bottom. Deal ends June 30.