REI offers the Evrgrn Grounded Cushion
in five colors (Blue Horizon pictured) for $14.93
. Opt for in-store pickup
to avoid the $5.99 shipping fee. That's $15 off and the lowest price we could find. It features two hidden drink sleeves, waterproof, abrasion-resistant bottom fabric, a removable shoulder strap, and it measures 18" x 18" x 6".