We just bought a new twin bed for our guest room/office. I have taken a few naps on it and it is nice. It is a serta perfect sleeper. The one where the counting have just lost their job because the guy bought a new matress.
We decided to get a King size one for our bedroom and priced them this weekend. For a king pillowtop serta perfect sleeper matress and foundation it will be $500. We will get it from Sam's Club. That is where we got the twin for less than $300 and that price included the bedframe too.
Go online to the wholesale club's and see what they want for what you want. They will also deliver if you order online. It is worth it to pay $30 or so for the membership if it will save you hundreds of dollars on a good matress. Besides, at those prices if you do not like the matress in a few years, it would not be like throwing away $5000 dollars. Happy hunting!