>>95968219
When my friends and I first got into playing D&D we would use grid paper from our schoolbooks and use shit like pencils, erasers and staplers as terrain. Our characters were usually represented by small pins or tacks. Good times.

Anyway, the beauty of something like that is ease for improvisation. Big beautiful maps can be great though, if you're planning on spending a lot of time in that area beyond just one session, or you are happy to re-use it. Premade maps can be fun for that.