Hi Kyleppil,
You have many options available and the first place I would start is post #1 here which has all the basic information, steps, and guidelines you will need to make the most suitable choice.
Because of your added preferences for a chemical free mattress … post #2 here (and the many posts and sources of information it links to) would also be well worth reading. There are many manufacturers that make mattresses that either use fire barriers that have no chemicals (such as wool or a viscose/silica inherent fabric) or with a doctor’s prescription will make it with no fire barrier at all (and save you any taxes as well).
If you let me know your city or zip code in southern NJ I’d be happy to let you know of any of the better options or possibilities I’m aware of in your area.
Phoenix