You said POLE BARN, I had mine built by a company out of OLK. that built 342 barns in a year, it is all they do. Mine is 30x50 clear span with wooden truss. Then I had a contractor pour the concrete after the pole barn was built. This is the cheapest route to take, they built the barn $1,000.00 cheaper than I could even buy the materials for and build it my self. If you go this route plan what doors you want and where and if you want utilitys under the slab or enter the side. Good Luck.