Home Depot has 8' 4x4 rounded landscape timbers marked down to $1.97. These make great fence posts and are every bit as good as $6-$8 line posts if installed properly. I have some at my old house that have been in the ground for 15+ years and are as good as the day they went in. They also have the dog ear pickets marked down to 1.25. Doesn't get much cheaper than this to build a fence.