If you want to live in a flat world with 3d miniatures inside it, you can try this cardboard scenery for your gladiators. It is easy to store, it is decent to see. Better than my orange flat arena that I use in my playtests for sure! Well, it is more a fantasy arena than a real one, but it give you the right feel, and it is very affordable. You can download the pdf here for only one buck, and than print it at a service near you if you want a large surface.