Hi Hoagy1969,
Post #1 here has step by step process (and some links to information) that can help you greatly improve your odds of finding a much higher quality/value mattress.
Once you have done some initial research into mattress materials I would always start with your better local manufacturers or retailers and if you let me know the city or zip you live in I’d be happy to let you know about the better choices or possibilities I’m aware of in your area.
If you do decide to go with the extra risk of an online order then some of the best quality/value online choices are in post #21 here.
If you are committed to memory foam, there is also a list of online memory foam sources in post #12 here (some of these are duplicates from the first list).
Phoenix
Phoenix