Hi Silk

Other than buying or renting some kind of GIS software, and seeing that you are a student with possibly limited funding, you could try GIMP, or Krita. I think the type of map you are describing could be better done in a piece of vector software, though. I use CC3, and in many ways it would be ideal if you can't afford the vector version of PS, as its a one time purchase for life, but if you have no money at all to spend on anything you could try something like Inkscape?

I'm not an expert on that software at all, but if you're lucky ChickPea might say a couple of things about it for you. It's her favourite software