How much does it cost to weld a Mustang Mach 1 uniframe together?

I'm contemplating buying a 1972 Ford Mustang Mach 1 for a full restoration. The only problem is, the frame was cut in two. I have been told it can be welded back together but i wanted to ask before i went any further to see if this is cost prohibitive.

That's a dumb idea. Go look for another car.

You can turn it into a stretch limo now! Add a few passenger door sections and viola! If you have to ask, you can't afford it. Find another frame, use the pieces of that one as spares, if you wish.

I wouldn't even think about trying to weld a unibody car back together.