Hi Clark,
Healthy foundations is certainly one of the better online options but they wouldn’t be my “standard” by any means. They only have one mattress rather than a range that can be tailored to an individual’s needs and preferences. In other words it’s an all or nothing proposition although their return policy is very good which can minimize the risk of trying them out.
There are some memory foam options in Post #12 here which have a wider range of choices, more versatility, can be adjusted for firmness and support in some cases, and have better value.
Phoenix