Chainlink mazes are pretty popular especially with strobes. I also like hog wire wire fencing with 6" squares, another cheap /free option is to use 6' privacy fences. I called several fence contractors in my area and said they could dump old panels at my place.
I ended up having to call them all and tell them o stop we had so many. with T posts and big zip ties they made great walls. I also had a stack of aged 4x4s to boot!