Queen size :S$149
This matress from IKEA is very good for me. The springs balance the uneven load[human body] laid on them and the flexibility of the matress is what keeps you sleep well.
I have also bought it with the BED FRAME from IKEA FJELLSE Bed frame $49 + $50 for hte wood strips on the bed frame that hold the matress.
Bottomline : You get a good comfortable sleep, no body pains for me and my wife also loves it.