Hi Cloudze110,
The first place I would start your mattress research is the tutorial post here which has all the basic information, steps, and guidelines you will need to make the best possible choices … and know how and why to avoid the worst ones and make meaningful comparisons between mattresses.
Whenever you see “green tea” in memory foam then you are most likely dealing with one of the many Zinus companies which includes Vivon and many others which means I would be very cautious because they tend to use some lower quality/density memory foams in their mattresses which can be a weak link in terms of durability. A forum search on Zinus or on Vivon (you can just click these) will bring up more information and feedback about them and you can read more about Chinese imports in general in post #6 here
The most important part of the “value” of a mattress purchase is how well it matches your unique needs and preferences in terms of PPP. Regardless of the cost or quality of a mattress … if you can’t sleep well on it then it would have little value to you.
Outside of PPP … a mattress is only as good as the quality of the construction and materials inside it so I would make sure that you know the information listed in this article so you can assess the specs against the quality/durability guidelines in post #4 here and make more meaningful comparisons with other mattresses.
Unless you can find out the quality of the materials in a mattress (regardless of the manufacturer) … there is no way to make any meaningful comments or assessments about a mattress.
Phoenix