Hi backpainAmy,
There are too many unknowns, variables, and preferences involved for anyone to tell you which specific mattress (or brand) to buy based on specs (either yours or the mattress) out of all the thousands that are available in the market (see mattress firmness/comfort levels in post #2 here).
The tutorial post here though has all the basic information, steps, and guidelines that can help you with “how” to choose the mattress that is best for you … and just as importantly know how and why to avoid the worst ones.
If you follow the steps one by one you will have the best possible chance to make a great choice and of course if you have any specific questions along the way you can always post them on the forum.
It also has all the information you need to make meaningful comparisons between mattresses based on the parts of your personal value equation that are most important to you. Price is certainly not the best way to determine either the suitability of a mattress or the quality/value of a mattress compared to others.
If you are comfortable with an online purchase then the tutorial post also has a like to some of the better online memory foam retailers and manufacturers I’m aware of as well. Many of these sell mattresses that are very similar to the Tempurpedic lineup so you can use your testing on Tempurpedic as a reference point. Post #9 here also has more information about the different ways that one mattress can “match” another one.
If the Tempflow/Selectabed showroom is close to you then post #2 here includes the better options and possibilities I’m aware of in the Greater Los Angeles area.
Phoenix