Sponge mattresses at your age are not good and have poor support. It is easy for people who are still growing up to cause spinal deformation, and mattresses are not suitable for strenuous exercise (hehe, I won't say the details). Sponge has a problem, that is, sleeping for a long time, the place where you often sleep is easy to collapse, making the whole mattress uneven; Besides, sponges are not cheap. If the price is low, I suspect that black cotton is used, which is very harmful to my health. You must pay attention.

According to your age and financial ability, I think you'd better buy a spring mattress. At present, the technology is mature, the performance is balanced and the price is reasonable. You can try to choose big brands according to your area, so that the quality can be guaranteed. Generally speaking, the number of 100*200 is around 700, and the number of 120*200 is around 900 (I think all brands are ok, for reference only).

If you buy a mattress of standard size, such as 120*200, 150*200, 180*200, and there are ready-made cloth covers for sale, you can go to the bedding shop to buy them!