Do places give away wood pallets where you are? not necessarily pretty, but can be quite functional. Sturdier if you can use at least a few t-posts here and there to stabilize. [I try to find pallets that I know haven't held chemicals, pick up most of mine from the local feed elevator, they don't have to ship them back, so dispose of them.]
I'll see if I can find any pictures of places I've used pallets, some are against sturdy fences, but they make more of a barrier than mesh for wily stallions. One place, I have 3-4 up for a summer fence, do have a couple t-posts inserted to make them sturdier.
Sometimes lumber yards have 4x8' pallets (sheet goods come on them), but usually they are shipped back to their supplier, you might still inquire, perhaps where you live they would give them away. I'm off to bring the mares in from pasture, so will get a picture of my short section of pallet fence, that is just pallet and t-post.
[Picture of Topper, pallets against his paddock mesh fence in the background. Can't find any better at the moment.]