H Four2Pool,
There are some guidelines here that may help you avoid some of the lower value choices and outlets in your area (such as the major brands and chain stores). Their sales are just marketing gimmicks and there are great value mattresses with better value than their best sale prices “negotiated” even lower available every day of the year at better outlets and factory direct manufacturers.
Some of the better choices in your area are listed in post #2 here.
Latex is the coolest sleeping foam although there are many factors that affect sleeping temperature (some of them are discussed in post #2 here) so the foam itself is only part of the puzzle. Some of the gel memory foam options may also be worth considering.
A forum search on “waterbed” (you can just click this) will bring up some threads that include people who were also transitioning from waterbeds and have information that you may find useful.
Phoenix