Hi,
If you have the time and the DIY skills, you can easily build one for that price.
I'd try that or;
craiglist, preloved, gumtree.
Go to Aquarium stores and buy the cracked tanks, they often have cracked ones at the back that are no use for holding water. You can use them. As you won't be holding water in them, you can get them nice and big for a cheap price. Just check the dimensions first.
My USA mate bought a 6ftx2.5ftx2ft tank for $110 as it had a crack in it.
-Rose, Zack, Izzy and Jess