Hiya,
I have a queen-sized Ikea mattress for sale. It's a nice foam mattress called Sultan Hedfors. You can read a review about it here.
http://www.memory-foam-buyersguide.co.uk/2008/03/31/review-ikea-sultan-hedfors-mattress/
It's about 1+ years old and was used in a guest room. I'm selling it for $200. Good condition, price negotiable.
Pictures of the mattress are here:
http://singapore.craigslist.com.sg/fuo/2016014330.html
Pls SMS or call 98755726 if you have any questions or are interested. Cheers!