yes they are expensive but for me it was worth it, my pony is on box rest, there is no risk of him pulling a net down and getting tangled adding more to my current telephone number of a vets bill, he is really comfortable using it, does not make a mess and is helping reduce the overdeveloped muscle that had built up under his neck.
I'm sure you could probably make one cheaper but for me it was worth the extra money for less hassle, my anti-DIY OH put it up really quickly and easily and it has stayed up (so Far)
I bought three horse size ones and my 14.1 can easily reach so get horse size as a youngster will only grow!
One of my horses is hopeless, if he goes in a stable with a haybar he pulls it all out over the floor, spreads it about and then eats it. But the others are fine, they don't pull it out and they save me loads of time. Much better for horses too as much more natural etc. Do put them a few inches up off the floor so you can clear them out from underneath though. I thought the pony wouldn't reach if it was off the floor and I have to lean over and pull out the rubbish/seeds etc by hand. Ouch.