I am looking to fence in 3-3.5 acres for a horse and some cows, and I am looking for the most economical wire (non-electrical) fence available, any suggestions?

That's a hard one. For cattle you need something tough since they will walk right through it. Although I have seen them walk through a barb wire fence. But yet you want something safe enought for the horses. We have pipe fencing with no-climb but that could get pricey on 3.5 acres (we have an 1 1/3). If I come across anything I'll let you know.

You could try barbless barbwire. We were just talking about it today! Never had a horse get cut on it yet.

Had the barbless wire or straight wire in Texas and the neighbors cattle just walked right through it like nothing was there. It's not like there was more grass on our side. Their pasture was in winter wheat.

Ok I know it would be more money, but horse wire with elect on the tip. We have so many costmer's that ask for that. It work's on horse's and cattle. Also if you pull it tight and right on the bottom of the ground, it stop's a lot of other animals from getting in your fence.
For my mini horse and goat lot's we have the horse wire behind a cross buck board fence. With being fencer's we wanted something nice looking, as for takeing care of our little critter's we wanted something that would do the job.
Like I said there are many way's you could do it, but most common around here is the horse wire, with eletc on top to keep all animals from leaning over it. This kind of fence will cost more, but in the long run it pay's for it's self.
Good luck and have fun with it.

We went around and tore down a couple old dairy barns and let me tell you that would is still standing for a 2 acre perimeter today! That was 10 years ago.

I don't think I would have the energy to do it today. I would go down to homedepot and hire some day laborers and let them demo it.

They may even be able to set it up? Anyway.. it always boils down to a cost consideration..