If you don’t have the time to build your personal arena, if you have the money to buy it, if you think that resin is a bad idea, you can always buy a ready made arena of coloured plastic. You can buy a Playmobil arena.

On this blog I find this arena used for 28mm gladiators. The aspect is good and the proportions are reasonable too. Its cross section dimension is 33 inches. And it comes from a garage sale, so it was more cheap to him. After its usage by children, now it can be used by children with an adult aspect.

It is sold at about 150 US$. You can looking for it on e-Bay, Amazon or you can buy direct from Playmobil. They have got an e-commerce website and this article is still available. I look on the UK localisation and this is the address for the item.