Hi Trxfred.
You are most welcome. 
Glad to be of assistance.
It is quite a bit to take in, to begin with, but I’d stick to the basics. To put it in very simple terms … Find a retailer/manufacturer that you can trust and who is willing to give you the complete mattress specifications which will allow you to assess:
~ mattress information listed here so you can compare the quality of the materials and components to the mattress durability guidelines here to make sure you’ll sleep well for the useful life of the mattress.
~ suitability of the mattress finalists to your Needs and Preferences to ensure that your body stays in neutral alignment during sleep and that you find the sleeping environment comfortable and can fully relax in it.
~ run all by your ~ personal value equation
Let us know if you have additional questions.
Phoenix