MiniInTheBox offers the Ultralight Inflatable Sofa Chair in 11 colors for $15.99. Coupon code "5309146SOFA" drops it to $9.99. With free shipping, that's the lowest total price we could find by $16. It includes a carry case and measure 98" x 28" when inflated.
Note: Be sure to uncheck "Add Insurance to Your Order" to avoid the 49-cent fee.