Hi Bigdon2013,
Welcome to the Mattress Forum!
Surface comfort (softness) and support are two different things, and you can have good support and still a soft surface comfort. You may personally prefer a firmer surface comfort, having a higher body mass. For a higher BMI, the key will be finding componentry that will be of appropriate quality for your specific situation, which will then give you the best chance at have a successful comfort life, so I would always make sure that you find out information listed here so you can compare the quality of the materials and components. Those in a higher BMI range want to be especially prudent in the choice of their components. For those in a higher BMI range, there is more information about selecting a mattress in the durability guidelines here. Specifically, if your BMI is 30 or higher:
Higher BMI ranges will need more durable materials and components in a mattress and in a BMI range of 30 or higher I would include any 1.8 lb polyfoam or 4 lb memory foam as a “lower quality/density” material (relative to a higher BMI only) and minimize their use to a total of “about an inch or so or less” in the mattress.
Polyurethane foam: If your mattress is one sided then I would look for 2.0 lb per cubic foot density or higher. If the mattress is two sided then I would use a minimum density of 1.8 lbs per cubic foot or higher.
Memory foam (or gel memory foam): If your mattress is one sided then I would make sure that any memory foam is at least 5 lb per cubic foot. If the mattress is two sided then I would use a minimum density of 4 lbs per cubic foot.
All foams are insulators to some extent, and they are just one part of your mattress microclimate. Post #2 here can help you choose the types of materials and components that are most likely to keep you in a comfortable temperature range. Generally speaking, Talalay latex is your most breathable foam, flowed by Dunlop latex, polyfoam and memory foam. An innerspring mattress can offer a bit more air circulation than some all-foam mattresses, but the items closest to your skin will have the greatest impact upon temperature. A firmer surface comfort, or a mattress that you are “on” more than “in”, will also tend to sleep a bit cooler. Don’t forget top of bed products like sheets and your mattress protector, your pajamas, bedroom temperature and even humidity. There really is quite a bit involved to assist you with sleeping as cool as possible, and the post I linked to covers this in great detail.
This makes things a little tougher for you, as the better quality and higher density materials will tend to be more expensive. I would not recommend the amazon mattress you mentioned. Instead, as you have a more restricted budget, post #4 here and the posts it links to include many of the better lower budget online options I’m aware of. You can see some comments about Lucid and other Chinese mattresses that are shipped compressed from overseas in post #6 here . A forum search on Lucid (you can just click the link) will also bring up more comments and feedback about them as well. Lucid mattresses tend to use low quality memory foam (3 lb density or less) which would be a weak link in the mattress in terms of durability and they generally aren’t a mattress that I would consider.
Even though you’re on a limited budget, the mattress shopping tutorial will have quite a bit proof useful information that can guide you through this process, in addition to the information I just provided you.
Let me know if you have other questions after you’ve had the time to read through this information.
Phoenix