I love this one:

Sleep Innovations Shiloh 12-inch Memory Foam Mattress

I've had others staying in our guest bedroom love it too and go out and buy one. At this point, with a number of moves and growing family, I've bought something like 5-6 of them.

I think Costco sells the same mattress under Novaflex or a similar name but at a slightly higher price point (the Amazon price varies quite a bit on the Sleep Innovations mattresses -- check CamelCamelCamel on it if curious).

I've moved a lot in the past few years, and each time buy a new mattress. Each time I've bought on Amazon, and to be honest, never had one I hated. Brooklyn Bedding, Zinus, etc. My favorite so far I took a complete gamble on and didn't expect much, but wow was I impressed. I have only had it 6 months so can't speak to its longetivity, but I sleep like a baby. It's a 'Revel' brand, here https://www.amazon.com/gp/aw/d/B07CZWQ97P/

Had this one for the last five years, it's been great: https://www.amazon.com/gp/product/B00828AQ9M/ref=ppx_yo_dt_b...

We bought a Zinus mattress recently. $260 for a queen size and pretty great so far.

Zinus, like the others have said, is usually pretty good.

I bought an AmazonBasics memory foam mattress about 15 months ago and have been happy with it. I think I paid about $240 for it.