My tailbone is not doing so well because of all the springs. Or something. But it'll of course take a while.
Well, memory foam is a good option, especially if it is fused with a cooling gel (god that is relaxing). It helps me, and it's allergy-free, especially with dust and dust mites. Plus there are some cheaper options out there in that department (do NOT go temperpedic, unless you like breaking the bank... while good, they can be $1,000 at times, if not more). Do a search, and you might find some good options.