For a standard straight line 5 strand bw fence on flat terrain, the materials should be < $1 a foot. Installed including materials $2 - $2.50, depending on the installer. Corners, gates, etc. will all add to the cost....
I agree with this on a standard barbwire fence. I paid $2.10/ft for labor and materials after I bought the materials on a 50" netwire fence a few years ago. I was quoted $2.50/ft turnkey. There was no dozer work involved. I built some fences on my own and only had about .50/ft in materials in those fences. That was on 4 wire barbwire cross fences. If you had to clear fenceline ROW then I could see it costing $3.50/ft. They build 8' galvanized material fences in South Texas for $3.50/ft including labor on cleared ROW. Price materials at McCoys or feedstores like M-G in Weimar. Depending on the type of barbwire cost per spool could range from $30 to $60. T-post will range from $3.50 to $4.00 each. Corners will depend on type of material used. I bought 10' tall 8"-9" top cedars for corners for $35/each. Treated will run more for the same size. Pipe is going to vary in costs but you have to included sakrete in your final costs. Line posts cost will vary but also on how many you use. A lot of the cost variance will depend on what type terrain it is built in, the type of fence you are wanting and what animal to keep in or out. Don't spare on the corner post size and depth, they are the backbone of any good fence. Ask your neighbor to cost share half of the fence. Many will help out.