Kohl's offers the Lux 8" Plush Queen Memory Foam Mattress for $424.99. Coupon code "TWENTY4U" drops it to $339.99. Plus, you'll bag $60 in Kohl's Cash with your purchase. (It can be redeemed March 27 to April 10.) With free shipping, and assuming you'll use the credit, that's $570 off and the lowest total price we could find. Deal ends March 23.