I want a mattress of amazon
Id recommend silent night entry level mattress, I paid £160 for mine and its best mattress ever had.
Specs won't tell you how it feels, how hard the springs are, how bumpy it is, and the give in memory foam. The same specs will also vary between manufacturers. Specs won't give you advice either. You'd be a fool to just go by specs but if comfort doesn't matter to you then why not....
I've had a two mattresses in the last 6 months, and at first they seemed uncomfortable. After a few nights of sleeping on them, they got a lot better!