You buy mattress that suits you first, then among the one that suits you the priced best.
My wife tried probably every single mattress store mattress out there due to her back pain and I narrow down to a list of requirement. If you are healthy and have tried mattress from similar construct you can tell what works for you or not then decide whether it is a good deal.
Memory foam sunk in, wife hates it, I hates it. It is out.
Latex is too bouncy on too small of a scale, it is out for my wife. I'm ok with it.
I love spring mattress but it is too hard for my wife.
Poly foam works best for my wife, but only with 1.5" to 2" comfort layer.
All foam mattress is not comfortable to me but to my wife, so we decided we need 2 separate mattresses instead.
Simmon Beauty Rest means nothing, they are just a name and you need to see the construction and see what is it going to feel like, likely try out hundreds of mattress and read on mattress underground to see the construction.
Don't forget you need to take your weight into consideration. Many low density foam (not soft, low density, you can make a suspension spring rate the same with either more rounds of coil and thick stiff spring or thinner spring with fewer rounds, but one will last longer than the other) will not last for heavy person.