Just noticed my old thread was mentioned. I with a 10 by 12 run in shelter. $200 for a solid rough cut wood floor on skids (usually very wet where I live so a dirt floor is bad), 2 by 4 frame, I was given plywood for $10 a sheet (it was used lightly), roofing is stuff called Ondura comes in sheet, cut with a utility knife and nail on. It cost around $600-$700 to make over a month and a half that we built it.
I replaced my paddock fencing for a 60 by 70 area, two strands electric fence for $200 including wood posts, insulators, good wire, gates and stuff like that.