Hi asmbc628,
I would treat the purchase of a mattress and an adjustable bed as two separate purchases and start with the mattress. An adjustable bed is more of a commodity and is really a matter of choosing the model which has the most desirable features for the price because any of them will feel the same under your mattress either flat or raised. A mattress is much more personal and individual choice that involves many more pros and cons you need to decide on to make sure it’s suitable for you in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences). Post #1 here has the basic information, steps, and guidelines that can help you make the best mattress choice.
The adjustable bed thread here has more information and some sources that you can use as reference points for good value and choosing the features that are most important to you.
Phoenix