By Forever 18 from Monroe, NJ
What about a child's gate that expands & is held with tension? You can often buy these at yard sales or discount places.
My brother and his family use a baby gate for an inexpensive dog gate they go to garage sales or thrift stores and buy two baby gates that would work together and make it into a dog gate and it recycles what the baby's once had :) and doesn't put trash back into the dumps.
lol I didn't see mulberry's comment
I'd get a plastic lattice panel at your local home-improvement store, cut it into panels, and edge each panel with thin wood of some kind, fasten panels together with hinges, and make more than you think that you will need so that you can zig-zag it and make it free-standing. Good luck.