Bought a new mattress last August and I'm as happy with it now as I was when I first slept on it. Amazingly comfy and supportive, no matter which way I'm sleeping [I have back issues and am a combo sleeper; Mostly on my side, in 'coma position', or occasionally my back].
Recommending because I love it, and because it was a pretty good deal imo.
Brand: Zinus
[I'm in Aus but it's an international brand, also available in USA, UK, Europe, Asia]
Mattress: Zinus Pocket Spring Euro Top Memory Foam
Description: It' a hybrid- iCoil innerspring with memory foam, plus inbuilt 'pillow'-type topper [Euro Top] appro 8cm. Total depth of mattress &topper is about 35cm.
Price: About AU$380/GBP£210 - Ordered through eBay and scored an 22% eBay Plus discount plus free delivery.
(It's a 'mattress in a box'; rolled up and vacuum-sealed, and was delivered to my doorstep 3days after ordering.)
*The only downside for me is that it's bloody heavy, so I have a difficult time lifting to tuck sheets when making the bed.