Insulating a metal shop?

I have a friend with a 40 x 60 I believe it is. He had it spray foamed. I'm tellin you now, if there's any way in heck you can get the money up, do it. Here in middle Georgia it gets HOT in the summer. We saw almost a 15 degree drop in air temp inside his building.
Can second this. A buddy built a 40x56 and spray foamed the walls and had blow in for the ceiling. A/c hardly runs in the summer. I think he had 4000 in the spray foam with application