I am considering sort of a do it yourself mattress. Either buying foam of varying densities or buying a solid inner spring mattress and using a good quality topper as a way to get good support for less money. I am wondering if anyone has experience with this approach and any suggestions about how to proceed?
Many of the forum members here have done what you are considering … some quite successfully and some not so much.
Before you consider designing and building your own mattress out of individual layers that you purchase separately I would read post #15 here and the other posts it links to so you have realistic expectations of the process and your odds of success and that a “spirit of adventure” and experimentation is more important to you than any cost saving you may realize (which may not turn out to be the case).