Reptile Hammocks, 2pcs Triangular Bearded Dragon Hammock Soft Breathable Hanging Hammock Net with Suction Cup for Large & Small Geckos, or Lizards(M)

Depending on if it is a young snake or a full adult, that should be passable I think, tho not ideal... someone chip in if you disagree! Considering the fact that you are just a kid yourself, a new full sized tank is going to be a really hard goal to reach for... instead, I would say go to the dollar tree and get some plastic bowls and fake leaves (just make sure the dye doesn't run if wet). You can flip the bowls upside down and use them as hides, just dig one side in a bit and push the dirt up around it in a way that lets you make a little opening at the front. You could also buy a couple of cheap items on amazon for cover like this set of plants and net platforms currently $13 with prime, or for something even cheaper, these platforms would probably be okay too, especially paired with dollar tree fake plants. Most things will be better than what is currently in the tank... Overall, know that this is not your job, but is a really common problem even today where classroom pets are not treated well. The fact that you are wanting to help make this animal's life better and came here for help speaks really loudly, and is very appreciated by those of us who are really passionate about this type of thing. If you feel comfortable, you or an adult could call the school and talk to a principal or superintendant to try and get a budget to get some items for the safety and comfort of the animals they are keeping. That is how real change happens a lot of the time, and you could make a real difference for a lot of pets that are likely not being well cared for.