I thought you meant a metal commercial building for your business. That isn't the same thing I was thinking. That is is just a light gauge garage, not a "metal building" that I was thinking of. Still, I could build a pole barn for less than that and put it up myself. $30k can buy a lot of material. You still need a slap, and any interior walls, insulation, etc. If it were me I would build a wood garage, but I am a contractor and don't have to hire someone to erect it. Looking at those pictures I have no idea how they get a 130 mph wind rating with that little bit of material. Not that you need that up there.
I would suspect the cost to frame the same building not counting sheathing and siding would be around $5k for walls, and maybe the same for trusses. I would call your local truss manufacturer and get a quote on the trusses, and then I could help you estimate the rest of the framing cost. Windows and doors will be the same. But you would have a building framed out of 2x6's and wood trusses that will last a LONG time. If there is a fire, that light gauge frame will melt just as fast as a 2x6. Now a red iron building is a different animal.
Some quick figures brings a wood frame garage with Hardi-panel siding and arch shingles to about $20,000 installed. Add the cost for the doors and windows and you are looking at about $5k-$7k cheaper for a 2x6 building over a light gauge garage.
Jeremy