Hi Danias,
Just in case you haven’t read it yet … the first place I would start your research is the mattress shopping tutorial here which includes all the basic information you will need to make the best possible choice … and know how and why to avoid the worst ones.
Two of the most important links in the tutorial that I would especially make sure you’ve read are post #2 here which has more about the different ways to choose a suitable mattress that is the best “match” for you in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences) that can help you assess and minimize the risks of making a choice that doesn’t turn out as well as you hoped for that are involved in each of them and post #13 here which has more about the most important parts of the “value” of a mattress purchase which can help you make more meaningful quality/value comparisons between mattresses in terms of suitability, durability, and value.
Once you get to step 3 in the tutorial then the better options or possibilities I’m aware of in the New York City area (subject to the quality/value guidelines I linked) are listed in post #2 here.
Good luck and I’m looking forward to finding out what you end up deciding … and of course any comments or questions you may have along the way.
Phoenix