If you can make something like 4 Ikea Lack side table units,that would be a massive upgrade.The end result is around 1,600 square inches.In the US,Walmart make extremely similar tables called the Parsons tables which are the same price however they're only an inch or two smaller.That isn't really important though,since the cage itself is always a square meter even with legs included!
It's honestly a really cheap and easy DIY,all you really have to do is mesh the sides(aka on the outside frame of the cage you have the table legs and each pair make the frame for a mesh wall).You'd have to line the end result with nonadhesive contact paper and then make lids and or doors,but it's still not a complicated DIY even at that point so pretty much anyone could afford and make that
