[Closed] Foam Mattress/Memory Foam Recommendations (campervan content)

Been looking at cheap foam mattresses on ebay and other sites, looking doesn't help much with working out what to buy when it comes to mattresses! Also can't decide whether to go for one with a memory foam top layer.

As they come rolled up with all the air sucked out, its not exactly an easy item to return, even if the seller does take them back if you're not happy!

So if anyone has bought one recently, where was it from andwhat do you think of it?

I need a small double size, fairly thin, 5 or 6" max. Going onto a sprung slatted base.