Now you are being silly.
Will bin all mine tomorrow and go drop 1k on each mattress else I'll be branded a cheap skate by @smadmad
Wrong. Unfortunately problems from sleeping on cheap mattresses won't manifest until they are adults and have problems with there back. They will like most adults think oh its wear and tear or age. When infact it's because their parents were cheapskates.
I have cheap mattresses for all 3 of my kids and had one when I was little, reality is cheap mattresses have weaker springs and less padding making them ideal for kids who weigh less. The reviews above have clearly been written by adults expecting miracles.
Didn't know they let 12 year olds register for hukd?