I researched before buying. You want to buy the firmest mattress possible with zero memory foam. Heaviest is best. I lifted every mattress in the store. A heavy mattress has more steel in it than a light mattress whcih would be more memory foam.

Buy a thick mattress pad to put on your new firm mattress. The mattress will last decades and the mattress pad will get replaced every 4-5 years.

Futon, willingly for the past 20 years. I have never had any back issue/ache that a nights sleep could not fix.

A piece-of-shit mattress meant for a sleeper sofa, on the floor, but at least it's new. If I flop onto it, my knee smacks the floor. But it's a queen size, and only cost $250 with delivery..

Purple California King. Replace your mattress at least every seven years brother. Your back will thank you

I am not picky! list so long depending on year of my life and if home or not : king size, queen, airmattress, waterbeds , WOODEN FLOOR in warmest room and coat for pillow, carpeted floors, ship spare hammock, sleeping bag, lazy boy recliner for years, van carseat, back of van. mainly I prefer a complimentary suite luxury hotel room paid for by someone else because it was prepaid and unneeded. Some of those were $5,000 a night.