Langria via Amazon offers its Langria Comfort 8" Tight-Top Innerspring Full Mattress for $189.99. Coupon code "Q5PL5HUP" cuts it to $132.99. With free shipping, that's $106 off and the lowest price we could find. It features an independently-encased pocket coil system, 15-gauge hardened tempered steel coils, tight-top foam padding, fire barrier, and quilted breathable top fabric.
It's also available in Queen for $160.99 with free shipping via the above coupon. That's $19 under our February mention and the best deal today by $49. Both deals end May 3.