DON'T waste your time with the lower end.......I learned the hard way.

I bought one of the lower end Miller units used for about $700.

I have a 6hp/60gal air pump, and the only thing it would cut, was plain 16 gauge sheet metal.

Even that was a little slow as you could do the same with metal cutting shears. My Acetylene torch would leave it in the dust.

It did OK with cutting out spot welds, but it would usually burn through the metal under the weld if you weren't careful.

I would recommend getting a PC that would cut through 1/4 with ease as you might need that feature one day.