If it's a standardized width and they can be assembled and trucked in, the price difference might be minimal compared to ground mounted (which also need metal s

If it's a standardized width and they can be assembled and trucked in, the price difference might be minimal compared to ground mounted (which also need metal structure, just one with supports spaced closely together). Increase the span, use a bit heavier gauge square tube and have a 2d truss structure