Hi navigates,
I would strongly encourage you to read the tutorial post.
There is nothing at Plummers or Macy’s that I would consider and I would completely avoid any Stearns & Foster or any of the other major brands or any mattress where you don’t know the quality of the materials inside it. The risks of this kind of “blind” purchase and the use of lower quality materials leading to buyers remorse and the need to replace the mattress much too soon is much too high in any budget range. If nothing else I would read the guidelines here (which are one of the links in the tutorial post).
I’m not sure where you are exactly but the Los Angeles list here or the San Diego list here includes the better options or possibilities I’m aware of in the same areas where Plummers has a store.
Phoenix